Rose growers choose many means to grow their roses. People who live in cooler climates don't experience long periods of the warm conditions roses need to survive. The solution is to grow roses in a greenhouse. Many rose species, like miniature roses, will bloom all year, provided that you learn how to grow them in a greenhouse properly. If your greenhouse dimensions and light saturation levels are sufficient, you can grow nearly any species of rose that you desire.
Remove plants from their shipping pots. Free the root balls and soil by gently tearing the root clusters.
Add fresh potting soil to each new pot you need. Fill about 1/3 full and mound up the soil.
Place your roses into the pots, draping the root clusters over the soil mound. This encourages healthy new root growth.
Fill the remaining amount of the pots with soil around the rose plant and roots and tamp down slightly. Your soil level should only be slightly higher than it was in the shipping pots.
Add water to the soil. Only add enough water to moisten the soil.
Prune your roses, using the pruning shears. Cut back all growth, height and width, to 3 inches from the main stem, including buds and blooms if there are any. Remove any dead branches.
Trim away any branches that will block the middle of the rose plant. When leaves grow, these branches will keep air from circulating through the rose plant.
Add the high-phosphorus fertiliser at each watering, weakened to ¼ the strength indicated by the manufacturer. Do not start fertilising your greenhouse roses until you see new growth from branches, leaves or buds. Maintain a daytime temperature of at least 15.6 degrees Celsius and a night temperature of no less than 4.44 degrees C. Use grow lights to help with temperature regulation if necessary.
Dead branches can be identified by snipping off a small piece at the tip; if the inside is brown the branch is dead. Leaving branch stubs on the stem will lead to regrowth. To completely remove branches, "slice" the branch stub or whole branch off the stem by sliding the pruning shear blade down the stem, carefully. Water your greenhouse roses when the soil starts to dry out; the soil must be moist at all times but not soaked.
During shipping, rose plants are not exposed to air, water or sunlight; you must transplant your plants immediately to ensure they remain healthy. Do not add water or fertiliser to the plant but to the soil instead to avoid damaging the roses.