Northern gardeners need to know exactly what zone a rose is hardy to. Southern gardeners must also watch to see what zones are recommended for each particular variety, as some roses perform very poorly in hot and/or humid weather. Read the catalogs carefully and, if possible, purchase your roses from a local or regional grower. They will be able to advise you from experience about how a particular variety will perform in your area.
as mentioned when I replied to Mick, the powder with be a fungicide as we’re trying to help prevent dampening off – although careful watering is always the best solution to this problem. The hydrogen peroxide mentioned in the blog will be the same as the hair bleach and is just an extra precaution taken by the author to sterilise her seeds. Using normal bleach in tiny quantities is usual practice in preventing harmful bacteria in seed processes, especially if they are prone to disease in the first place.
Fertilizer: Roses are heavy feeders, and will benefit from a steady supply of nitrogen, phosphorus and potassium. You can provide these nutrients with either liquid or granular fertilizers, at a ratio of approximately 5-8-5. In most cases, regular applications of compost, rotted manure, fish emulsion and seaweed extracts will provide roses with all the nutrients they need. These organic amendments also help to moderate pH imbalances and stimulate beneficial soil life. Other organic amendments favored by rose growers include greensand, black rock phosphate and alfalfa meal.