Fertilising Strawberries: Home Remedies & Natural Fertilisers at a Glance

How to Fertilise Strawberries

For healthy growth, strawberry plants primarily require the main nutrients nitrogen, phosphorus and potassium. Calcium, magnesium and trace elements such as iron, boron, manganese and zinc are also essential in comparatively small quantities. Compared to most other crops that you probably grow in your garden, strawberries have a low nitrogen requirement. If they are over-fertilised, they react with excessive leaf growth at the expense of flower and fruit formation. They also become more susceptible to disease! This does not mean that they do not need nitrogen fertilisation at all, but only in moderation. Much more important are nutrients such as potassium and phosphorus, which are very important for flower and fruit development and the quality of the fruit. For this reason, it is particularly important with strawberries to know which fertilisers you can use and how often you should fertilise.

Which Fertiliser Is Suitable for Strawberries?

To fertilise your strawberries, you should use slow-release organic fertilisers. Organic fertilisers have several advantages, as they not only nourish your plants, but also the soil life. They promote the build-up of humus and thus help to improve the soil structure and therefore the availability of nutrients and water retention capacity. Organic fertilisers also act as slow-release fertilisers, as the nutrients are metabolised by soil life over time and gradually made available to the plants. In order for the fertiliser to work well, you should always work organic fertilisers well into the soil, unless they are applied in liquid form. In addition, a regular supply of water is very important after a fertiliser application so that the plants can also absorb the nutrients through their roots.

Mineral fertilisers, on the other hand, are known to have some negative effects on the environment. The easily soluble nutrient salts are very mobile in the soil. This means that although mineral fertilisers have a rapid fertilising effect, they are also easily washed out and can therefore pollute the groundwater. In addition, they are not suitable for fertilising salt-sensitive plants such as strawberries. Strawberries naturally grow in locations with a low mineral content and light, humus-rich soils. Strawberry plants react to small amounts of salt with discolouration of the leaves or even death and reduced growth. For this reason, we recommend that you make or buy your own natural fertilisers for sustainable gardening. If you would like to read more about Natural and Organic Fertilisation, take a look at our article on the subject.

Fertilise Strawberries With Compost: What You Need to Keep In Mind

Compost is a well-known organic fertiliser and you are probably wondering whether you can fertilise your strawberry plants with compost. It is very difficult to give a general answer here, as the composition of compost varies greatly depending on what organic material you use in the compost.

The composition of your compost depends primarily on whether you add plant or animal matter to the compost. Animal waste in the form of manure usually causes the salt concentration in the compost to increase and should only be used with caution (especially chicken manure!). This is not so good for strawberries, as the proportion of water-soluble salt may then be too high and your plants will suffer as a result. In contrast, compost from green waste or organic waste contains fewer nutrient salts, although it still contains a significant amount. We therefore recommend using compost as a basic fertiliser, which you can work into the soil when planting or a few weeks later. Around 3 to 5 L/6 to 10.5 L of compost per m2/1.2 yd2 is sufficient.

Compost is quite balanced in terms of nutrients and contains nitrogen, phosphorus, potassium and trace elements. Compared to other organic fertilisers, the nitrogen content is significantly lower and only slowly available to plants. On average, green waste compost contains less nitrogen, phosphorus and potassium than compost from organic waste. With a basic fertilisation with compost, your newly planted strawberry plants will be well supplied with the main nutrients phosphorus and potassium as well as trace elements and these will usually last until after the second harvest. Only nitrogen should be added moderately with horn shavings or other organic fertilisers if necessary. It is important that all composts are well matured. This ensures that all pathogens in the compost are killed and do not damage your plants.

Fertilising Strawberries With Horn Shavings

Horn shavings or horn meal is an organic fertiliser that is rich in nitrogen. In contrast, other main nutrients such as potassium and phosphorus are only present in very small quantities. Therefore, horn shavings are not suitable as the sole fertiliser for strawberries. However, if you have made a basic fertilisation with compost, you can use horn shavings to add nitrogen. Due to their slow effect, the strawberry plants are evenly supplied with nitrogen, which reduces the risk of over-fertilisation. Another point to bear in mind is that horn meal slightly acidifies the soil. However, this is not a problem with strawberries, as they like to grow in slightly acidic soil anyway.

Recommendation for Fertilising With Horn Shavings:

Source: https://lwg.bayern.de/mam/cms06/gartenakademie/dateien/erdbeere_duengung_infoschrift_3202.pdf

Fertilise Strawberries With Horse Manure

If you want to use manure as a fertiliser, you should note that there are big differences in the composition depending on the animal species.

• Horse manure, for example, contains comparatively little potassium in contrast to other animal manure and also has relatively little nitrogen and phosphorus. Fertilising with horse manure alone would probably not be enough and you should mix it with other organic fertilisers such as compost and horn shavings.
• The same applies to cattle manure: high potassium content with a relatively low nitrogen and phosphorus content. However, cattle manure has the advantage that it has a low salt content, which is beneficial for strawberries.
• Pig manure has a fairly balanced composition of phosphorus, nitrogen and potassium and also contains quite a lot of magnesium.
• Chicken manure has a very high nitrogen content, while potassium and phosphorus are present in lower proportions. In addition, chicken manure has many water-soluble salts, which is why it is rather unsuitable for strawberry plants.

Of course, these contents depend heavily on the feed and vary greatly, which is why it is not quite so easy to fertilise according to requirements. It is best to always supplement manure fertiliser with suitable other organic fertilisers for a good nutrient supply. In general, however, manure can have a positive effect on the soil structure (similar to compost) and provide your plants with nutrients in the long term. However, you should not use fresh manure as fertiliser if your plants are already on the bed. This would damage the plants. Either work in the manure in the autumn before planting in the spring. Or you can use dried manure in the form of pellets. This also has the advantage that spreading is much more convenient and you can easily work the pellets into the soil. The last option would be to compost the manure. However, as already mentioned, you must fertilise carefully, as compost contains more nutrient salts, which may not be good for the strawberry plants.

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Tomato Fertiliser for Strawberries

Tomatoes and strawberries have similar nutrient requirements, so special tomato fertilisers are very suitable for your strawberry plants. These fertilisers usually contain more phosphorus and potassium than fertilisers for vegetable plants. In addition, tomato and berry fertilisers often also contain a small amount of magnesium, which also has a positive effect on the quality and growth of the fruit. So if you have little experience with organic slow-release fertilisers and are afraid of over-fertilising, we recommend buying this fertiliser. The packaging will tell you exactly how to apply the fertiliser so that you don't over-fertilise and your plants are well cared for. Make sure it is of good quality, preferably organic, so that the fertiliser does not contain any harmful residues.

DIY Fertiliser: Homemade Remedies & Natural Fertilisers

In addition to fertilisers that you can buy, there are also some home remedies and fertilisers that you can easily make yourself at home. These include coffee grounds fertiliser or plant dips made from nettles. You can also make compost in your own garden and easily create Your Own Compost. If you don't have the space for this, you can also set up a Bokashi Bucket in the kitchen to produce your own organic fertiliser.

Coffee Grounds as Fertiliser for Strawberry Plants

Coffee grounds are a widely used household remedy. These contain the main nutrients in a more appropriate ratio, although nitrogen still dominates. However, these nutrients are generally only present in very small quantities. Therefore, coffee grounds are more suitable for fertilising during the season if you notice deficiency symptoms. Coffee grounds also have an acidic effect on the soil, but this is more of an advantage for strawberries. For many other crops, however, coffee grounds should be used with caution. If you want to fertilise your strawberries with coffee grounds, you should dry them well first. Otherwise, you run the risk of mould forming in the soil. Then mix the coffee grounds with water in a ratio of 1:1 and water the plants with it.

Fertilise Strawberries With Nettle Slurry

Nettle liquid manure is also a good organic liquid fertiliser that contains a lot of nitrogen, potassium and silicic acid. You can therefore also use nettle liquid manure to give your plants a boost during growth. The silicic acid also strengthens your plants, making them more resistant to fungal diseases and pests. Here too, however, the exact composition is unknown, which is why you should not rely solely on nettle manure to fertilise your strawberries. You should also be aware that liquid manure can have a negative effect on the taste of your fruit. Therefore, only fertilise with nettle slurry as long as there is no fruit on the plant. You can find out How to Make and Use Your Own Nettle Slurry in this article.

When to Fertilise Strawberries?

In general, fertilising strawberries is often divided into several applications. As strawberries are perennial plants, they are usually fertilised about once or twice a year. However, this can vary slightly depending on the strawberry variety, as everbearing varieties may need a little more fertiliser than single-bearing strawberries. The first fertilisation is applied in spring when the plants are planted. Normally, the amount of organic fertiliser is then sufficient for the entire year. If you have a very sandy, light garden soil or notice signs of deficiency, you can fertilise again in the spring of the second year. Otherwise, it is sufficient to apply fertiliser again in the autumn after the harvest in the second year. A good supply of nutrients is particularly important after the harvest, as this is when the plant forms new flower buds for the following year.

Fertilising Single-Bearing & Everbearing Strawberry Plants: The Right Time

When fertilising single-bearing and everbearing varieties, the timing and frequency are different. This is because everbearing varieties have a higher nutrient requirement due to the constant production of fruit.

• Single-bearing strawberries are usually only fertilised once in midsummer after the last harvest. For these varieties, it is important to fertilise in autumn and not in spring. Spring fertilisation has little effect on your harvest, as the flower buds of the strawberries are already laid in the previous autumn before the winter dormancy. To ensure that the plant is well supplied with nutrients, you should ensure a good water supply.
• Everbearing strawberry varieties are also fertilised several times during the growing season. Start by fertilising in spring with slow-release organic fertiliser and then provide the plants with organic liquid fertiliser at regular intervals if necessary. You can then apply fertiliser approximately every 4 to 6 weeks. Even after the last harvest, they will appreciate a fertiliser application with organic slow-release fertiliser such as horn shavings. Keep a close eye on your plants and react if you notice any deficiency symptoms. But don't over-fertilise either, as this will make the strawberries more susceptible to disease.

Examples of popular strawberry varieties and a List of Single-Bearing and Everbearing Varieties can be found in this article.

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