Gardening Articles: Care :: Plant Care Techniques
No-Soil Gardening (page 3 of 5)
by Howard M. Resh
The best way to start seedlings is to sow seed in rock wool cubes or blocks, available at garden centers or hydroponic retail stores. Soak the cubes in water for 24 hours before sowing seeds to adjust the pH and thoroughly moisten the cubes.
Buy seeds of varieties known to grow well hydroponically. Examples are 'Cobra', 'Boa', 'Caruso', 'Match' and 'Trust' tomato; 'Britania', 'Corona', 'Carmen', 'Futura', 'Marillo' 'Mustang', and 'Niagara' cucumber; 'Delphin', 'Goldstar', 'Luteus', 'Samantha', 'Tango', and 'Wonder' pepper; and 'Deci-Minor', 'Ibis', 'Impulse', 'Ostinata', and 'Yvonne' lettuce. Seeds are available from hydroponic retail stores as well as many mail-order seed companies.
Plant tomato and pepper seeds in 1-inch cubes, then transplant them later into 3-inch blocks. Sow lettuce seeds into 1-inch cubes and don't transplant them into blocks. Sow cucumber seeds directly into 3-inch blocks. In each cube or block, sow two or three seeds for most vegetables, four or five herb seeds, and one cucumber seed (cucumbers germinate very well, and seed is expensive). Thin (with scissors) tomatoes, peppers, and lettuce to one plant per cube once the first true leaves begin to form.
After sowing, water the cubes and cover them with polyethylene to keep in moisture; check daily and remove the cover as soon as germination occurs. Immediately upon germination, place the seedlings under light.
Transplanting. Transplant lettuce when the first set of true leaves appears, 10 to 14 days after sowing. Transplant herbs at a similar stage, but note that the time until true leaves appear may be considerably longer. European cucumbers take two to three weeks, and peppers take five to six weeks.
Transplant tomatoes into 3-inch rock wool cubes after the first true leaves unfold, in about two weeks. When two pairs of true leaves have formed (three to four weeks after sowing), transplant them to the growing system.
When transplanting, be careful not to damage the tender roots underneath the blocks or cubes as you set them into the holes in the growing channels. Have the solution circulating before you set in the plants; that way, the blocks will immediately receive nutrient solution.