Fertilising roses properly and tips on rose fertiliser

Alongside pruning, fertilising is the most important regular task in caring for the 'queen of flowers'.

Fertilising roses: why do roses need fertiliser regularly?

Roses are heavy feeders and should be supplied with enough nutrients so that they grow strongly and bloom abundantly. Besides nitrogen, which is responsible for strong growth, they above all need phosphorus for plentiful flowering. At the latest in the second year after planting you have to apply rose fertiliser, as the natural reserve in the garden soil has been used up.

Fertilising roses: already when planting?

We advise against fertilising at planting time; well-established roots are more important than superficial growth of the shoots. Instead of fertiliser, organic soil improver can be added, which stimulates healthy soil life and helps the rose to settle in. An exception is horn shavings, which act with a delay and can already be put into the planting hole.

Once the rose has established its roots at its site, it can be fertilised for the first time. For roses planted in spring and early summer, the right time is roughly after the first flowering. After that you can keep fertilising until about the end of July.

Rose fertiliser: organic or mineral?

Our recommendations refer to organic rose fertiliser. We rather advise against liquid fertiliser and mineral rose fertiliser.

An organic complete fertiliser for roses releases its nutrients slowly and indirectly via the soil. It allows the plant to grow naturally and sustainably. Over-fertilising is almost impossible. Pushing roses up too fast with mineral fertiliser such as Blaukorn leads to unnaturally fast growth. The rose may then react with increased susceptibility to diseases and reduced frost hardiness.

Environmental tip: many organic-mineral fertilisers contain rock phosphates / soft-earth phosphates. This also applies to products marketed as particularly sustainable / 'vegan' - it is worth a look at the ingredients. Their production and extraction is - to put it mildly - "a huge mess", phosphate reserves are limited and adding them to fertiliser for the home garden is unnecessary. If you manage your garden sustainably, you should do without rock phosphate as an ingredient in fertiliser.

We therefore recommend the organic rose fertilisers from OSCORNA, horn shavings and, in spring and autumn, soil activator to improve natural soil life:
All prices incl. VAT and shipping within Germany

Fertilising roses: when and how often?

Established roses are fertilised 2-3 times a year.

The first and most important fertilising date is at the start of the growing season in early spring (together with pruning) or in late autumn once growth has stopped. It should be generous and take place before the plant is in full growth. At this point the nutrients are supposed to be there already.

The second application is especially important for repeat-flowering or continuously flowering bedding and shrub roses. It takes place after the first flush of flowers in June together with the summer pruning and is somewhat smaller in quantity than the starter dose. Once-flowering varieties should get a little less, climbing roses and rambler roses correspondingly more.

For very good, frequently reblooming varieties or continuous bloomers, a further feed can be given around the end of July. A gap of about 3 weeks between applications should be kept, though.

Fertilising roses: letting them ripen from late summer

In the second half of August, a dose of potash (Patentkali) ensures that the newly formed shoots ripen well. Only well-ripened shoots with stable cell walls survive even longer cold spells in winter without frost damage, and susceptibility to fungal diseases is reduced. A further positive effect is more intense colours in the blooms and healthier green foliage. The dose should be applied before heavy rain or finished off with thorough watering.

In late autumn or early winter, soil life can be promoted with soil activator where the soil is heavily used. Organic long-term fertiliser that is released via the soil can also be given once the rose has stopped growing.

In addition to the annual feeds described above, iron deficiency can be counteracted if the foliage turns strongly light green. It arises in strongly alkaline soil, which converts the iron. The remedy is to correct the pH value in the winter months with acidic substances such as ammonia or urea, or by mixing in peat. Spontaneously giving iron fertiliser in summer helps in the short term and is recommended. In the long term, the aim should be a healthy soil that is not too alkaline.

Fertilising roses: applying the fertiliser correctly

For rose fertiliser to take effect, it has to be worked into the soil. To do this, loosen the soil superficially around the rose. The fertiliser is then scattered and lightly worked in by hoeing.

Fertilising roses: the perfect time

It is best to apply rose fertiliser shortly before rain is due or in generally damp weather. The water lets the fertiliser combine well with the soil, and it is not blown away by wind or eaten by pets / a dog. If a fertilising date is due and no rain is forecast for a longer time, you should still keep to it and water afterwards.

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Saving tip: when buying fertiliser you can also get roses or clematis delivered 'free of charge':

Here you will find our => organic rose fertiliser and => soil improver

Instead of an organic or mineral complete fertiliser, many hobby gardeners prefer to fall back on what they already have, or make fertilisers for their rose plants themselves. We give an overview and explain whether and when fertilising in the garden with them is worthwhile.

• Compost
  Home-made compost is often not perceived as a fertiliser, but usually contains a natural mix of nutrients. There is absolutely nothing against adding some compost to the rose bed every spring or topping up tubs with it.
  
• Coffee grounds as rose fertiliser
  Coffee grounds accumulate in almost every household. Their composition resembles commercial products - potassium, nitrogen, phosphorus, tannic acid and antioxidants are contained. In addition, the powder can improve soil structure and water retention. It is important that it is dried and not used straight from the machine. Coffee grounds are not entirely unproblematic for roses, though: because of their low pH value they can make the soil acidic in the long run. This can be countered with lime or soil activator. Whether you use strong or decaffeinated coffee does not matter; caffeine has neither a positive nor a negative effect on the plants, and no effect is known on earthworms and other soil organisms either.
  
  Our tip: the widely used paper coffee pads are particularly suitable for tub roses. They are practical to handle and allow a consistent dosage.
  
• Cow manure, farmyard manure and horse droppings for roses
  It is no coincidence that manure is also called 'dung' - used correctly, it is THE natural fertiliser par excellence. It is especially important that it is well rotted, as fresh manure contains a great deal of harmful ammonia. It should be worked well into the soil, preferably in spring or late autumn. Which kind of manure you use matters (almost) not at all; farmyard manure (cow manure) and horse droppings are probably used most often. Caution is advised with chicken manure and manure from other poultry - it is much more aggressive and should not be applied neat.
  
• Nettle liquid manure, horsetail liquid manure
  Brews and decoctions made from nettles or field horsetail have been a popular home remedy for many years. For fertilising, mainly the brew is suitable. It is left to ferment for several weeks in large containers, usually barrels, and then applied with the watering water.
  
  Decoctions are sprayed on the leaves several times from the start of sprouting; they also have a slight fertilising effect here. Mainly, however, they serve to strengthen resistance to the usual rose diseases powdery mildew, black spot and rose rust.

For all home remedies: since the composition and thus the NPK value are not known, you have to find out the dosage yourself. It can also change depending on the age and quality of the starting materials. Their effectiveness should therefore be checked regularly on the rose plants fertilised with them. In general, we also do not recommend them as the only fertiliser, but a combination with organic rose fertiliser or horn shavings can be very effective.

Horn shavings, horn meal / horn grist and horn fertiliser are long no secret tip among rose lovers. The difference behind the names of these pure nitrogen fertilisers is the grinding degree, and with it the time when the fertilising effect starts and how long it lasts. While the fine meal acts quickly, the coarser shavings are an excellent long-term fertiliser that works for up to several months; horn grist lies somewhere in between. This cannot be stated exactly because the activity of the soil life - and thus the temperature - also plays a role in the conversion.

Horn fertiliser supplies only nitrogen, i.e. the N in NPK, at about 14 - 16%. It is therefore not a complete fertiliser and mainly promotes growth.

=> everything about the effect and use of horn shavings / horn grist and horn meal