The next step how to grow roses from seed is to sprout the rose seeds. After having gone through their “stratification” time, take the containers out of the refrigerator and into a warm environment of around 70 F. (21 C.). I do my best to time this for early spring when the seedlings would normally be coming out of their cold cycle (stratification) outside and starting to sprout.Once in the proper warm environment, the rose bush seeds should start to sprout. The rose bush seeds will usually continue to sprout over the course of two to three weeks, but probably only 20 to 30 percent of the rose seeds planted will actually sprout.Once the rose seeds sprout, carefully transplant the rose seedlings into other pots. It is extremely important not to touch the roots during this process! A spoon may be used for this seedling transfer phase to help keep from touching the roots.Feed the seedlings with half strength fertilizer and be sure they have plenty of light once they start to grow. The use of a grow light system works very well for this phase of the rose propagation process.The use of a fungicide on the growing rose seeds will help keep fungal diseases from attacking the rose seedlings at this vulnerable time.Do not over water the rose seedlings; over watering is a major killer of seedlings.Provide a lot of light as well as good air circulation to the rose seedlings to avoid disease and pests. If disease does set in on some of them, it is probably best to eliminate them and keep only the hardiest of the rose seedlings.The time it takes for the new roses to actually flower can vary greatly so be patient with your new rose babies. Growing roses from seed can take some time, but you will be rewarded for your efforts.