Once cuttings are planted and watered, place them under a flourescent lamp where they will stay until rooted. Softwood cuttings require bottom heat of about 21°C (71°F), which is usually room temperature for most propagation areas. Keeping trays of cuttings on cold concrete floors will slow down root development. Avoid high temperatures in the tray as they force the cuttings to produce top growth instead of roots, using up food reserves in the cutting.
High humidity levels help reduce water loss from the cutting’s leaves, but they can also encourage plant diseases to multiply and attack your young plants. If you use a clear dome over your tray, remove it at least once a day for a few minutes to “air out” the tray, and wipe condensed moisture out of the cover, it simply interferes with light reaching the cuttings.
While domes can reduce water loss from cuttings they can also trap heat. Keep the flourescent lamps at least a foot (30 cm) above the top of the dome. A small thermometer placed in the propagation tray will help keep track of propagation temperatures.
Since cuttings cannot spend their whole lives under a dome, the sooner they can adapt to life in open air, the better. Once cuttings have lived inside the dome for a week or so, by removing the clear cover for a few hours during the light period, watching carefully for wilting. If they do show signs of stress, replace cover and try again a few days later. While some crops take longer than others to root, plants that seem “addicted” to their covers may be suffering from fungus disease – treat with “No Damp” according to directions. The other possibility is high temperatures inside the dome. (above 24°C = 75°F )
FEEDING AND WATERING
Newly planted cuttings are “watered in” well with a mix of water and powerthrive (one tablespoon/ one gallon) to supply vitamins that reduce plant stress, and also to provide good contact between the cutting’s stem and the grow medium. If the cuttings are cared for under moderate conditions (21°C tray temperature, fluorescent lighting ) they will likely not need watering for about 59 days. Plant rooting in fast – draining mediums such as perlite or hydrocorn may need watering more frequently. Once cuttings can stand up well with the covers removed, they will need watering more often. Keeping cuttings too wet will cause root and stem rot; letting cuttings dry out will kill them just as quickly . Let experience and the appearance of the cuttings be your guide.
Giving new cuttings fertilizer can actually cause slow rooting – the plants have no good reason to grow roots! Once cuttings show signs of having new roots- either fine white roots showing on the bottom of the rockwool cube or new light green top growth start feeding cuttings with mild fertilizer solution. A good “baby food” for newly- rooted cuttings is 1/3 strength flowering fertilizer. This food helps the new plants to grow deep, strong roots, without forcing top growth When cuttings are definitely rooted and producing new top growth, with the dome permanently removed, lower the florescert lamps gradually closer to tops of cuttings, watching closely for wilting or signs of stress. It’s possible to gradually drop the lamp within 8cm (3 inches) above the growing tips. If you are keeping these rooted cuttings under the fluorescent lamps, be sure to raise lamps as plants grow taller to avoid cooking new top growth Continue watering and feeding as required, using mild fertilizer until they are transplanted to stronger light levels.
Keep Fluorescent lamps on for 18-24 hours a day while cuttings are rooting . Once rooted and being fed the mild fertilizer solution, they will need a six hour night to grow best. Match the timing of the dark period of the cuttings to the night, they will have when transplanted into a grow-room or greenhouse.
FUNGICIDES AND PESTICIDES
Since cuffings are taken from healthy, disease and pest-free stock plants, and the grow mediums we use for rooting cuttings are considered disease-free at the start, we usually don’t have to use fungicides until a week or so after starting the cuttings – use “No Damp” fungicide solution as a foliar spray or water it into the medium. (1 Oml “No Damp” with one litre of water) Repeat once a week as a precaution while cuttings are rooting.
Insects can be very destructive to young plants. Spider mites and fungus gnats are two of the worst insects to discover in a propagation tray, since they can destroy all the cuttings and set back the garden. “Bug Kill” works well against spider mites – be sure to spray underside of leaves regularly to kill adults and hatchling as they emerge from eggs. Spray inside of tray to pick off strays crawling from plant to plant.
Fungus gnats lay eggs in the grow medium, and when the eggs hatch, their tiny larva chew new roots to suck food from the plants. They weaken plants and create disease problems too. They carry fungus spores on their bodies, which attack plants through their damaged roots. Use “sticky cards” to check for signs of Fungus gnats In the propagation tray, and treat all cuttings with Wilson’s “Potting Soil Insecticide Dust” or similar mild pesticide if signs of gnats appear.