Visionary Cactus Guide
GROWING 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.
Water your Cacti seldomly, 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.
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!
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.
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.
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.
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 cactiphile explains.
About a couple weeks before the first hard frost (see Farmer's Almanac for dates) I make sure that the soil drys 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 temp 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 Tricocereus 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 RootTone (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.
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. Tricocereus 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, unpot 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 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 thru 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 unpotted and thoroughly cleaned. Of course all rotted or dead parts are removed. The plant should then be repotted in pure sand and kept dry at a temperature between 64 - 70 degrees. Cactus are tough and are designed to withstand long periods of drought, they should start growing again when healed and watered.
The only pests that may plague your Cactus collection are scale insects belonging to the superfamily Coccoidea, and nematodes. Of interesting note, one species of scale is 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. If nematodes are present, the plant must be unpotted and the roots cut off. It is then repotted in a sterile mix till rerooted. The soil should then be sterilized and all infected matter burned.