Growing Cacti from Seeds
Growing Cacti from Seeds.
(My book “Hoodia Report” has some 23 pages of instructions about growing Hoodia.)
The fastest and cheapest way to increase the size of your collection is to grow the plants from seeds. In the nurseries even the cheapest, smallest cacti will cost you more than a standard packet of cactus seeds. Out of a packet of 20 seeds with a reasonable germination rate you should get about 15 seedlings. Even after some losses to rot, snails, etc., you should still get about seven plants beyond the first year. You should keep at least two of the plants for your self and either swap or sell the surplus. Buying a few dozen varieties for a few years would provide you with a collection of a few hundred species. Though they are slow growing plants, many of them will flower and produce seeds within 2 - 3 years. Then you can swap seeds for plants. One grower in Queensland worked out that if he has a 17.5% survival rate, he breaks even.
Most people fond of cacti would start their collection by buying plants from nurseries, or other cactus collectors. Because cacti look so different to all other plants, most people are afraid to start growing the plants from seeds, thinking that the propagation is very, very different to growing other plants from seeds. In fact, there is very little difference. Once they try it, they find it easy enough to grow just about any of the seeds. But of course, there are some exceptions. Taking into consideration the habitat in which a particular species grow will make it much easier to adapt the right technique for germinating the seeds of that particular species. Given the right conditions, they are among the easiest plants to grow - they have to be - in the desert there are no cactophiles to nurse them, to wrap them in cotton wool and spoil them rotten, no special soil mix with the right pH, right proportion of washed river sand and potting mix, no strelization, fungicide, insecticide, herbicide, fertilizer for succulent plants - only occasional rains and very poor soil
The most practical approach to avoid a disaster is to start with seeds that are very common and have the standard price. That will mean that the species is either easy to grow, thus providing plenty of seeds to keep the price down, or that the species is wide spread in the habitat, indicating that it doesn’t require very specialised conditions for growing, or both. Even if you should fail with some of them, don’t get discouraged. . With each species that you grow, you will learn something new. The financial loses won’t break you. One of my customers in Queensland worked out that if his success rate is 17.5%, he breaks even.
I think it was George B. Shaw, who said “You see God at work in your garden” and indeed, when I see some seeds sprouting, I feel like a God’s apprentice. When I had success, I almost felt God patting me on my shoulder and telling me - well done my boy - you're learning fast - keep it up. And when I failed, I understood that God was telling me that I am overambitious with difficult plants. I almost hear God saying: “Son, you still have a few things to learn”. If you fail, don’t give up. Just remember the varied habitats that succulents grow in: from the frozen tundras of Kamchatka to the Death Valley. From the coastal deserts of South America where it never rains and the plants live on moisture captured from sea mist, to cacti that grow in moss on rocks next to waterfalls. The habitats are extremely varied and you can’t provide the ideal growing conditions for all the cacti and succulents in a glass house in the suburbs of Melbourne.
The growing instructions below are very general and apply to the vast majority of cactus species. As you get more experienced, you will be tempted to grow something more challenging. Succumb to the temptation, but before that, learn as much as you can about the species that you want to grow. The better informed you are, the better your chances of success.
Always try to saw the seeds at the start of their natural growing season, for a vast majority of plants it is in spring (but there are a few succulents with growing season in winter. Abraham Lincoln once said about lying to voters: “Sometimes you can fool all the people. Some people can be fooled all the time. But you can’t fool all the people all the time!” The same applies to growing seeds. You can fool some of them with artificial lights and temperatures, but you will get the highest germination rate if you will plant them in spring.
Buy fresh seeds; their percentage of germination is usually greater than that of old and indeterminate stock. To be sure of the quality buy only from established seedsmen. Some fresh seeds will germinate within a few days or a week, but the seeds of some species are notorious for slow germination. If you don’t use all the seeds that you bought one year keep them for the next year. They will be still good - Mother Nature designed them to survive several years of unfavourable conditions.
For best germination you will need to provide proper conditions. These factors include temperature, light, moisture, soil, etc. While all species have their own set of requirements, most of the easily available seeds will germinate in the same seed raising bed. To increase your rate of success, you can separate North American species from South American species. (Most of South American cacti need more humus in the soil mixture.) As you become more experienced, you can go into finer divisions of your seeds.
The light is mainly a factor after the seeds have sprouted. Light controls the direction the tiny seedlings grow, the roots go away from the light into the soil and the tiny stem grows up towards the light. For most cactus and succulent seedlings the light level should be rather high. The seedlings themselves will tell you about the light requirements. If they are getting tall and lanky and will not stand up then they need more light. If they are bright red AND not growing they have too much light. Many seedlings are naturally tinged red so do not worry about this. Depending on your geographical location, you can grow them without any shade cloth in less bright areas, or up to 60% shade cloth during summer in very sunny areas. In winter you may need shade cloth only in tropical and subtropical areas.
The temperature is a very important factor in germination, as many species will only germinate if the temperature pattern falls within certain limits. This limit depends mainly upon how the species behaves in its natural setting. For example summer growing cactus (like Ferocactus) germinate best at higher temperatures, and strictly winter growing plants germinate best at cool temp. Varying the temperature between day and night is very helpful - most cacti grow in deserts, where the temperature swings between day and night can be quite big. So simulate the natural swing present in a natural setting by having the temperature rise in the day and cool off at night. When the temperature swings like this you are more likely to hit an optimum level for better germination.
Moisture is also very important, as the water has to be absorbed into the seed to allow germination to take place. During germination the water should be clean, do not use a lot of unnecessary chemicals before the seedlings are well up. Things like fertilisers will retard germination so use primarily clean water. Some people like to use fungicidal products during germination and this should be done according to the instructions on the product.
The soil is very important for several reasons. The soil provides water, nutrients and gases needed for germination and growth. There is no single universal soil mixture which is best for all cactus and succulents. As a general guide the following mixtures work well in most cases:
For most North American cacti (except epiphytic species ) and most mesembs & Chilean species:
50% coarse sand (for making cement) [finished soil can be a little alkaline]
30% natural sandy loam, screened
20% grit (pumice, perlite, etc.)
For South American cacti and most other succulents except Crassulaceae:
50% coarse sand or: 1/3 coarse sand [finished soil slightly acidic]
50% sphagnum peat 1/3 sphagnum peat
1/3 perlite
For tiny seeded species, like Crassulaceae, and tiny cactus like Strombocactus, Parodia, etc.
50% coarse sand
50% perlite,
or 100% sphagnum peat, in sealed plastic bags.
Be very careful about the sand, look at several types and make sure that it will not compact in age. Concrete sand from a sand and gravel company usually is a good type to look at first. A good sand should have different particle sizes and contain many small stones. The sandy loam soil should not be sterilised unless you have serious pests, like nematodes. Natural soil has very beneficial bacteria present that help plants grow much better. When the odd weed seeds will sprout, pull most of them out, but leave a few as they help you ‘read’ the soil moisture very well, as they quickly wilt when the soil dries out.
Fill the pot to almost the top with your mix, and lightly press it level with the smooth end of a small board. Carefully sprinkle the seeds over the surface. Tap the pot gently on the sides to work the seeds into the soil a little. Large firm seeds like Peniocereus can be pressed into the soil with the same small board. Large fragile seeds like Aloe can just be buried with additional soil mix so they are covered. Then you can sift some powdered charcoal over the surface of the soil, which helps to keep the soil surface free from algae. Another trick to prevent the growth of algae is just to cover the seeds with a very thin layer of your seed raising mix and then with a few mm layer of white coarse sand (1 - 2 mm grains). The grains will dry before algae can start growing on them. And the grains will block off the light from the surface of the soil thus preventing the growth of the algae. The coarse grains will also provide good support for the growing stems of the seedlings. The tiny seeded types also prefer a more humid atmosphere during germination, so an enclosure to raise the humidity is very helpful. Distilled water is very helpful for tiny seeded types until they have germinated.
After the pots are planted, just set them in the greenhouse in a germination chamber where the sun can shine on them. You can use a wooden frame, lined with plastic, to hold the pots, and cover the chamber with nylon window screen. Window screen as a cover allows free flow of air, which discourages problems like fungus and algae. A fog nozzle on your hose is a very good way to provide adequate mist. After misting the chamber the screen holds many tiny water droplets which raises the humidity inside. You can mist them frequently, depending on the weather conditions, just make sure the grit layer stays moist while the seeds germinate. Mist them heavily the first few days to load the pots with moisture and to stimulate the seed to absorb water.
After germination has started, slack off slowly on the misting, but keep them moist most of the time. After the seedlings are all well up and starting to grow, slack off more on the water and let them dry out occasionally, so they do not rot. This takes practise and no firm schedule can be given. No seed should be kept constantly moist for weeks on end. Some species take extra time to germinate and they should not be kept moist for an extended time. Keep them moist for a few weeks, and then if no germination happens allow the pots to dry out for about a week. Then re-mist the pot to soak it up with moisture again and continue this cycle of wet/dry for several cycles. Some very hard to germinate species can take a few years to sprout. When the pots are well up and most of the seeds that will germinate have done so, remove the pot from this high mist area and you can place the pot among your older and adult plants.
Transplanting is not recommended until it is needed. Each time you move a seedling it has to generate a root system and this only retards growth. As long as the seedlings have room to grow and they are healthy, leave them in the same pot. For this reason use a pot that will hold the seedlings for as long as practical. A suggestion is to plan on keeping the seedlings in the same pot for 1-2 years, so avoid planting a high number of seeds in a small pot. If you do not have a greenhouse then start the seeds either where they receive sun for part of the day or start them under lights. When started under lights you may have to give supplemental heating from below to give proper temperatures, as the light tubes do not provide warmth like natural sunlight does.
Fertilise your seedlings after the germination is essentially over. Then use water soluble types and apply it with your regular watering. Use a rather weak formula, something in the range of 1-2-2 or approximate. Add a trace element mix to your feeding so they have the essential nutrients. Apply fertilisers during their active growth period, for cacti mainly in the spring and summer.
Some species have very fine seeds, things like Strombocactus, Aztekium, Parodia, etc. These types need a more closed humid atmosphere. An easy way to do this is to cover the germination chamber with an additional layer of clear plastic film. Keep this plastic film over the chamber until germination is well started. Then remove the plastic and keep the nylon screen over the chamber as this will help the tiny seedlings to get established. Try to keep the soil moist for quite awhile as these plants need a more careful and steady moisture level to help them get a root system established. The nylon screen cover can be left on for several months until the seedlings are well rooted. The fine seeded types should be sown in their own chamber so you can give them the special care they require. If you have hard water an occasional use of distilled water or rain will help with these species, as hard water deposits can choke off the young roots. The key factor with growing these types is frequent misting without turning the soil stagnant from excessive moisture, this takes practice. Another method is to sow them in milled sphagnum moss with the pot closed inside a plastic bag made moist with distilled water. Keep the bag closed until the seeds have finished germinating and they are starting to make a root system.
Pediocactus, Sclerocactus and Toumeya.
Winter is the best time for sowing Pediocactus, Sclerocacus and Toumeya. In places with hard frosts in mid winter, you can sow the pots outdoors to give exposure to freezing/thawing occasions. In habitat there will be more than 100 nights with subfreezing temps, while during the day the sun will warm the air to thaw the ground surface. (If you live in an area where there is no frost, you will have to place the seeds in your freezer for a few weeks and when you saw the seeds place the tray with seeds in your fridge every night for a few weeks, even after the seeds germinate. If you can afford it and have a room for it, get an old fridge and use it for germinating the seeds. Set the freezer to just below freezing point and bring the seed tray out every morning.)
Then, in most of these habitats there will be some rain or snow in the spring. Also, in spring the ground will be cool and very damp. Many seeds will germinate in early spring under cool damp conditions, after the needed freezing/thawing cycles of mid winter.
In the summer often it is dry, occasionally there will be thunderstorms. .The ground will experience very high surface temperatures, be mostly dry, but occasionally very wet when thunderstorms come frequently in short bursts.
If you live where sharp frosts occur in the winter, try to sow the seeds by the end of January if possible, so that enough freezing/thawing cycles can occur.
Summary of sowing method used in New Mexico:
Sow in mid winter, keep mostly dry, occasionally wet, freeze at night and thaw in day.
Damp in early spring when cool, occasional light frost, warmer in day. Keep evenly moist and germination will start.
Very hot in mid summer, mostly dry with occasional soaks. More germination will occur after thunderstorms soak the pots. Avoid prolonged soaking now.
Mostly dry in fall, occasional soak only. Allow to dry out for winter dormancy. Sometimes plants will bud in the fall, do not keep the plant any warmer for the winter, just let the buds sit until spring when it would naturally flower anyway.
The nursery in New Mexico uses only the naturally occurring temps, there is no protection from cold at all. The pots are sown outdoors in plastic pots. The pots are housed in wooden boxes which are covered with nylon window screen. Suspended above the boxes is a layer of shade cloth. These two layers will break up heavy rain drops and give protection from hail.
If long heavy rains are possible where you live, it would be best to put the pots under cover after some germination has taken place. The outdoor treatments are designed to accomplish germination. .For example the plants do not like long soaking rains in late summer and into the fall, so you might have to move the pots to an unheated greenhouse or coldframe once they have sprouted. However a long soaking rain is very beneficial in promoting germination.
The easiest to sprout are: Pediocactus simpsonii, Sclerocactus spinosior, pubispinus, and brevispinus. They will often sprout in early spring when it still freezes a bit at night. They find early spring a very active growth time when it is cool and moist.
Sources of information:
Propagating instructions pamphlet by Mesa Garden, New Mexico.
Ian R. Shillabeer - Cultivating Cacti, Mini Gardening Books, 1969
Following is a compilation of various files from different web sites:
Growing Tips for our spiny friends
Cacti are part of a larger group of plants called succulents. Through natural selection most Cacti species lost their leaves, which allowed too much evaporation in the desert. Their stems became thick, and round to minimize surface area, and to store water. To protect themselves from the Sun and predators many species developed spines and hair, waxy skin, along with bitter alkaloids.
Most Cacti do fairly well as house plants, but however they are quite slow growing. Be sure and save the sunniest spots in your house for your Cactus plants as they need lots of light. Don't forget to turn them every few weeks so that they are evenly illuminated. If you are going to grow some of your Cacti to flower, or for seeds, then don't move them while in bloom. They are very sensitive to disturbances at this stage and can drop the buds.
Strange as it sounds, you can sunburn even a Cactus. If you are going to put your Cactus outside, they must first be acclimatized. Keep them in the shade for a few weeks, and then move them into partial sun. Don't be in a hurry to scorch them under a hot July Sun, give them a month or more to get gradually used to it. If after you put it outside your cactus starts to acquire a lighter green or tan tint, it is probably sunburned, move it to some shade.
Watering
As a rule water your Cacti seldom, and be very careful not to over water. Cacti and other succulents prefer hot and dry conditions and a soil that affords good drainage and aeration. Let the soil dry out completely between waterings during the growing season, and water even less during the winter. When watering your Cactus don't forget to use lukewarm water, cold water can shock the roots. A good way to test if your cactus needs water is tom poke a small, clean redwood stake in the soil. If it comes up with small particles clinging to it, then the soil is still moist.
Different Soil Types
A good soil mix is essential if you expect good growth and health for your Cactus. They prefer a porous alkaline soil. Contrary to popular belief, Cacti don't grow well in plain sand. There are several good brands of commercially available Cactus soils that come prepackaged. For those of you who want to do it yourself, here are a few recommended soil formulas. Ingredients are available at most garden centers, or larger department stores.
1. Equal parts commercial potting soil and builders sand. Also add one Tablespoon each of ground bone meal and ground limestone per gallon of mix.
2. Three parts course sand, one part loam (good rich soil), one part leaf mold.
3. Two parts soil mix, one part fine to small size pumice, one part leaf mold.
If you are making your own soil it would be a good idea to sterilize the mixture by baking in an oven at 400 degrees F for 60 minutes. This kills most bacteria, larvae, weed seeds and insect eggs.
Tip: Be sure and put a 1 cm deep layer of gravel on top of the soil surface. This will help secure the plant and help avoid base rot.
Fertilizing your Cactus
All mature actively growing cacti need to be fed occasionally. It is best to use a formula specifically designed for cactus like 7-40-6. (Nitrogen, phosphorus, potash) Use a mixture with a low ratio of nitrogen, as cacti can be burned by it. A commercial formula such as miracle grow or rapid grow can be used, but should be diluted to half strength. I have heard that "cactus juice" brand by Sudbury (1-7-6), is highly recommended. Regular Bone Meal, available at most Garden Centers, makes an excellent organic fertilizer. Don't forget the macro-nutrients like Iron (Fe), Calcium (Ca), Sulfur (S), and Magnesium (Mg). Also important are the micro-nutrients Copper (Cu), Zinc (Zn), and Manganese (Mn).
San Pedro especially, does very well indoors behind glass. A location where the plant gets at least 4 hours a day of bright, direct sunlight is ideal. The best possible situation would be a South facing sliding glass door, and a reflective screen placed behind the Cactus to redirect and concentrate the light.
Many Cacti have beautiful and fragrant flowers, but they can be quite hard to get to bloom. The optimal conditions to induce flowering are, a cooler temperature (especially at night), reduced day length (12 hours or less), and variations in nutrients (lower nitrogen levels). Try putting your Cactus in a dark, unheated garage (not below freezing) for a few weeks. Forcing can also be done inside, but you need a place next to lots of glass that stays cooler than the rest of the house.
Planting/Transplanting
Cacti prefer to be in unglazed clay pots with a layer of course gravel and charcoal in the bottom. Most Cacti have far ranging lateral roots so a shallow, wide clay pot is preferred. Be sure not to put your cactus in too large a pot because that can lead to later problems. A tall narrow pot often leads to stress and stunted growth.
Avoid transplanting too many times as this can also shock the plant, pick one size and stick with it a while. The best time to transplant is during the spring. Have a plastic fork on hand to help poke soil into those tight places. Clean off any loose soil that might be stuck to your plant with a small brush. Don't water for a few days.
A tip to remember. When handling small Cacti, use a pair of tongs, and for larger ones, use a rolled up newspaper. Cactus spines can be very sharp and can penetrate gloves, as you may well become aware of. Ouch!
KEEPING CACTUS ALIVE IN WINTER
During the dormant period (winter) your cactus should be watered only enough to prevent it from shriveling. Don't water at all if it is humid for an extended period. During dormancy water is not taken in as rapidly by the plants roots, nor does it evaporate as quickly, and the result might be root rot. If possible bring your cactus inside the house and place it by a sunny window so it can continue to grow (slowly) through the winter. There are however other methods, as this cactophile explains.
Cacti are well suited to being packaged for extended periods without light or water, they will almost always arrive at your house in good condition. As most species are cold resistant, they can be shipped any time of year. Since Cacti are tough and hardy, they don't have to be shipped by an overnight service, like most tropicals.
Mark Miller writes:
About a couple weeks before the first hard frost (see Farmer's Almanac for dates) I make sure that the soil dries up completely (shielding the plants from rain if required). Then I just move the containers inside my garage to protect the cacti from freezing. The temperature in the attached, but unheated garage drops to about 38 degrees during the coldest part of Winter. There is no window, or lights available. The cacti remain sheltered in the garage, in total darkness, all Winter until I bring them out in the Spring after all danger of frost is past.
I usually keep them under a shaded patio for a week or so, and slowly move them to partial direct sun, then full sun over the course of two weeks (they are subject to sunburn if exposed to direct sun immediately after emergence from the dark.) They are watered lightly each week unless water is provided naturally by rain.
When they are accustomed to full sun (May / June in my zone 5/6 location) I use Miracle Grow plant food (as directed for container plants, even though they are exposed to the rain outdoors.) I usually repeat fertilizing every 3 weeks or so during the Summer.
By July there is usually some good new growth which is very explosive in August and continues (slower) into late September. By late October the cycle continues and they are again placed in the dark shelter of a garage.
GROWING FROM CUTTINGS
Note: When harvesting a large Cactus, make sure that it is at least 18 inches (46 cm) long. Cut the Cactus into 3 equal size sections with a sterilized blade. Do this by making one slice 1/3 of the way from the growing tip, and another slice 1/3 of the way from the base of the plant. (Soil level) Leave the bottom, rooted section to regrow, use the middle section for your purposes, and use the top piece to root as a cutting.
When rooting a Trichocereus species, take a cutting that is at least 15 cm (6 inch) in length. I have heard that cuttings as small as 2 cm (1 inch) thick can be rooted, but I advise a larger section. Be sure and take the cutting from a growing tip. Cut several shallow nicks in the ribs close to the bottom of the cutting. Set it in a cool dark place until the bottom becomes dry and hard to the touch (somewhat like cork).
The section is now ready for planting after being dipped in a rooting hormone like Root Tone (use per instructions). The section should be inserted about 7 cm (3 inch) into a commercial cactus mix. Be careful as the pot will probably be top heavy. Keep the cutting in the shade and let the soil dry out completely between waterings (watch for rot). Cuttings might need an occasional misting at their bases if they fail to root or shrivel.
Some cluster forming Cacti, such as Mammillaria can be easily separated from the mother plant after they start forming separate roots. Just carefully break them off of the parent plant with a gentle, twisting motion ( a sterilized knife may be needed for those stubborn plants ). Plant the young starts as you would any other cutting, just remember to slightly bury the plants and cover all roots.
GRAFTING TECHNIQUES
Cacti are almost unique in the fact that they can be easily grafted. This is the process of joining the stem or a piece of a plant on to the rooted section of a different plant. Trichocereus make an excellent grafting stock for slower growing cactus. Grafting is best performed in the springtime, when the plant is growing at its most vigorous. The process is as follows:
With a sterile knife, (either by alcohol or flame) cut the top off of the plant that will be used as the base. Bevel the edge of the top slightly, to form a shape like an upside down pie plate. Make sure to trim off all of the spines along its edge to prevent misalignment. Sterilize your knife and cut a thin slice off of the top of your base Cactus again. Leave this slice in place as it protects the cut surface. Next, un-pot the plant that is going to be on top and slice off its roots a small way up the stem (remove any dead, dry areas). Again sterilize, and bevel, and cut a protective slice just like before.
Just before you join the two pieces (the scion and stalk), discard the protective slices. Be careful to align both plants sets of growth rings. You should push them together firmly because you want to be sure that all air bubbles are squeezed out. Carefully secure the plants in place using twist ties, rubber bands, or string weighted down with bolts. Do not over tighten, you don't want to strangle it, just hold it firmly together.
Do not water your plant or place it in the Sun for a few days to a week, give the graft time to seal. Then remove the bindings and slowly acclimatize your new friend to its surroundings.
Peyote has been known to increase its growth rate markedly if they are grafted on to the tips of faster growing Cacti like Opuntia. That leads me to an interesting question. Has anyone ever grafted several Peyote buds on the tips of a large, multi-branched San Pedro? It would probably look something akin to a scraggly X-mas tree, with a general conical shape, but a dozen or so thick arms, each tipped with a large cluster of bulging buttons. Hmm, gets one to thinking.
GROWING CACTI FROM SEED
A preferred method of growing from seed, from the good people at the Soma Graphics. My thanks to them for many good tips and ideas.
Cacti should be germinated in sandy, well-drained soil. A commercial sterilized cactus mix works fine. Use small ceramic pots 5 x 5 cm (2 x 2 inch) since they allow soil to dry out completely (after germination) and prevent root rot. Most cacti germination temperature should be around 70 degrees F. Peyote should be around 80 - 90 degrees.
Place a small piece of cotton over the pots drainage hole and pull a few strands through to act as a wick. Fill the pot with cactus mix. Place the seed on top of the soil in the center of the pot. Additional soil should be sifted through a tea strainer to barely cover the seed.
Put the pots in a Tupperware container with a translucent snap-top lid."Bottom" water the pots by pouring about 1/4 inch of tepid water (never cold) into the Tupperware. Bottom watering causes the roots to grow strong, from searching for the water. When you first plant the seeds, you should also top water once with a fine mist water sprayer. The soil should be well watered throughout but not soggy. Place the lid on the container and place it outside (April - July) or under artificial lights (For an earlier start indoors).
The Tupperware creates a mini greenhouse, and should be kept closed except for a daily check on the seeds progress (which allows some necessary air circulation) until the seeds germinate. They don't need any additional watering or misting during this time (unless for some reason the water level in the container drops below 1/16 inch). Be careful that your mini greenhouse isn't too humid. Wipe off any beads of condensation that form on the containers lid. Also be careful that the temperature isn't too hot, as this can cook the seedlings.
Many species germinate within a few weeks. When the seedlings first appear, they look like tiny green spheres. After they have sprouted, replace the Tupperware lid with a piece of stretched muslin secured with string or a rubber band. This will allow air circulation, which can be increased by placing a fan above the container. Adequate air circulation is essential as all green plants require plenty of CO2 to grow. Seedlings are more sensitive to light than mature plants. They should be dark green. If they are a reddish or brown color, they are receiving too much light, and additional pieces of muslin must be placed over the top of the container to shade them. If they are yellowish then they are not getting enough light.
When the seedlings have germinated, place a thin layer of very fine aquarium gravel on the surface of the soil. This gravel will help to support the new seedlings and protect the surface from drying out too quickly. Be careful to gently scoop out any green moss-like growth that might appear because of high humidity.
After four to five months (when spines have formed on seedlings) remove the muslin shading for one or two hours a day to give the seedlings more light. Stop bottom watering and use a watering can twice a week. Water around the seedlings, not on top of them. The seedlings should be misted occasionally (not a lot) in hot weather. Seedlings should be brought inside for their first winter, and kept moist (they cant handle very cold weather). They should be placed in a sunny window away from cold drafts.
Also note: The use of some sort of fungicide when germinating cacti seeds is almost mandatory due to the high humidity levels involved. I have heard reports that the fungicides Daconil and Consan 20 can cause reduced germination rates, and are not recommended. I have heard a recommendation for the brand name Chinosal, but have not used it personally.
GROWING CACTUS INDOORS, UNDER LIGHTS
It is recommended that a minimal level of illumination to grow Cactus indoors is around 15 watts per square foot (150 watts/ sq. meter). Fluorescent lighting should be placed 12 - 15 inches (28 - 35 cm) from the top of the plants. High Intensity Discharge Bulbs should be placed considerably further away (depending on wattage). Plants do much better if the day length is kept more or less constant, depending of course on the season. Be sure and use a timer set to 12 - 18 hours a day. Most plants grow best if the light, dark period matches that of their native habitats. When using artificial lights, be sure and use reflectors to catch and concentrate as much light as you can on the individual plants. For maximum growth, your plants should be rotated about every two weeks to assure even illumination.
Cactus, like most plants are more sensitive to certain frequencies (colors) of light. This is usually towards the blue and red parts of the spectrum. For best results use a grow light type of tube for fluorescent lights, or for killer results, step up to a metal halide. These kind of lights produce more light in the colors that the plant can use.
Metal Halide fixtures also produce a great deal of heat and some UV radiation, your Cactus will love it. These fixtures have proven to work well in an indoor environment as they have been used by "closet" growers successfully for years.
DISEASES AND PARASITES OF CACTUS
Usually Cacti are very disease free, but occasionally. Especially if the plant is over watered, any part may be susceptible to molds or rot. If the roots are infected, then most probably the core is also and the plant is lost. If an above ground part of your plant is affected, the area should be cut out with a sharp knife to remove any infected matter. The cut parts should then be dusted with sulfur or a fungicide.
If any of the roots are affected then the plant should be un-potted and thoroughly cleaned. Of course all rotted or dead parts are removed and burned. The plant should then be repotted in pure sand and kept dry at a temperature between 64 - 70 degrees F. Cactus are tough and are designed to withstand long periods of drought, they should start growing again when healed and watered.
Usually the only pests that may plague your Cactus collection are scale insects belonging to the superfamily Coccoidea, mealy bugs, and nematodes. Of interesting note, one species of scale is intentually grown on Opuntia Cactus so that their eggs can be harvested and made into a red dye.
An environmentally friendly method of controlling scale is to spray the plants with a mixture of rubbing alcohol and nicotine. Make sure to coat the entire surface of the plant. If nematodes are present, the plant must be un-potted and the roots cut off. It is then repotted in a sterile soil mix till rerooted. The infected soil should then be sterilized or discarded, and all infected matter should be burned.
Gibberellic Acid for Fruit Set and Seed Germination
John M. Riley
The following information is taken from a article by John M. Riley that appeared in the 1987 CRFG Journal (vol. 19, pp. 10-12). See the back issue information for price and ordering information.
The Germination Process
The first stage of germination consists of ingesting water and an awakening or activation of the germ plasma. Protein components of the cells that were formed as the seed developed, became inactive as it matured. After an uptake of water, the system is reactivated and protein synthesis resumes. Enzymes and hormones appear and begin to digest reserve substances in the storage tissues and to translocate the digested substances in the storage tissues to the growing points of the embryo. The sequence of the metabolic pattern than occurs during germination involves the activation of specific enzymes at the proper time and regulation of their activity.
Control is exercised by four classes of plant hormones: inhibitors such as abscissic acid which block germination; auxins which control root formation and growth; the gibberellins which regulate protein synthesis and stem elongation; and cytokinins that control organ differentiation. Ethylene is also believed to have a control function in some plants. Sometimes the last three controls are used together to crash through dormancy in germinating difficult seed.
Gibberellic Acid
Gibberellic acid (actually a group of related substances called gibberellins) was discovered as a metabolic byproduct of the fungus Gibberella fujikuroi, which causes the stems of growing rice to elongate so rapidly the plant collapsed. Synthetic forms of gibberellic acid are available commercially.
Gibberellic acid (GA) is a very potent hormone whose natural occurrence in plants controls their development. Since GA regulates growth, applications of very low concentrations can have a profound effect. Timing is critical: too much GA may have an opposite effect from that desired; too little may require the plant to be repeatedly treated to sustain desired levels of GA.
Effects of Gibberellic Acid
- Overcoming dormancy. Treatment with high concentrations of GA is effective in overcoming dormancy and causing rapid germination of seed. Concentrations of about 2 ppm can cause tubers to sprout earlier.
- Premature flowering. If a plant is sufficiently developed, premature flowering may be induced by direct application of GA to young plants. This action is not sustained and treatment may have to be repeated. Formation of male flowers is generally promoted by concentrations of 10 to 200 ppm., female flowers by concentrations of 200 to 300 ppm. Concentrations of more than 600 ppm markedly suppresses initiation of both male and female flowers.
- Increased fruit set. When there is difficulty with fruit set because of incomplete pollination, GA may be effectively used to increase fruit set. The resulting fruit maybe partially or entirely seedless. GA has increased the total yield in greenhouse tomato crops both as a result of increased fruit set and more rapid growth of the fruit.
- Hybridizing. Pollination within self-incompatible clones and between closely related species may some times be forced by the application of GA and cytokinin to the blooms at the time of hand pollination.
- Increased growth. GA applied near the terminal bud of trees may increase the rate of growth by stimulating more or less constant growth during the season. In a Department of Agriculture experiment, the GA was applied as a 1% paste in a band around the terminal bud of trees. Treatment was repeated three times during the summer. Walnut tee growth was 8.5 ft. for treated trees, 1.5 ft. for untreated trees.
- Frost protection. Spraying fruit trees at full-blossom or when the blossoms begin to wither can offset the detrimental effects of frost.
- Root formation. GA inhibits the formation of roots in cuttings.
Recipes
Although GA is not listed as a "poison", the following precautions should be observed: Flush with water any GA that may get into the eye. Avoid skin contact if possible. If skin contact is suspected, wash with soap and water. Do not re-enter an area after spraying until the GA spray is fully dry. Avoid ingestion of GA.
The powder may be dissolved as specified below to give the desired concentration.
|
Concentration |
GA |
Water |
Purpose |
|
50 |
125 |
2400 (10 1/2) |
Early flowering |
|
200 |
125 |
600 (2 1/2) |
Early flowering |
|
800 |
125 |
160 (2/3) |
Blossom set |
|
2000 |
125 |
60 (1/4) |
Seed germination |
|
1% paste |
125 |
5 ml (1 tsp.) lanolin |
Growth promoter |