Roses are extremely heavy feeders and need a sufficient and, above all, correctly composed supply of nutrients. In addition to the question of which fertilizers are even suitable, the right time for fertilizing also plays a major role. This article outlines different annual schedules for optimal fertilization with different forms of fertilizers.
Spring is fertilizer time
Annual plan for purely organic fertilization
At best, fertilize your roses with purely organic means, because cattle manure and horn shavings (32.93€) provide the plants with all the important nutrients. In addition, with organic fertilization, the risk of over-fertilization - to which roses react very sensitively as well as to undersupply - is extremely low. Organic matter breaks down gradually and very slowly, so the nutrients get to the rose little by little (as needed) rather than all at once. Furthermore, organic fertilization stimulates soil life by promoting the "good" bacteria in manure and compost. Fertilize preferably with cattle manure (€18.80) because compost should primarily be used to improve the soil.
Start with organic fertilization very early in the year
If the weather is suitable - the ground should no longer be frozen - start spreading cattle manure, horn shavings (32.93€) and/or compost as early as February, but by the end of March at the latest. Work in the fertilizer well and loosen the top layers of soil after the long winter to activate the soil. In the months of May to June, mature compost is worked in again before flowering. The last fertilization (ideally with cattle manure and/or compost) is done again in late autumn between October and November. This point in time differs from the other fertilization schedules, because mineral fertilizers etc. should no longer be fertilized in autumn.
Provide roses with mineral fertilizers
Short-term mineral fertilizers should only be administered very carefully in order to avoid unnecessary environmental pollution (e.g. of the groundwater). In any case, many gardens are oversupplied rather than undersupplied with nitrogen. Depending on the weather, start the season between mid-March and late April with short-term fertilizers, then fertilize again between early June and mid-July and finish this fertilizing cycle with potash fertilizers between mid and late August. Potassium fertilizers are generally said to increase frost resistance, so a dose in late summer can't hurt. However, it is more important for the timely maturation of the new shoots before winter that no more nitrogen is given from mid-July. However, you can make fertilizing easier by giving mineral long-term fertilizers, which only have to be given at the beginning of the season in March.
tips
So-called special rose fertilizers are commercially available, which usually consist of a combination of organic and mineral components and are specifically mixed for the special needs of roses. These are usually applied once in March and once in early summer (if possible before flowering).