Fertiliser school – How to choose the right fertiliser

Which fertiliser should I choose?

Chicken manure

Composted chicken manure is very rich in nitrogen and is suitable for cabbages, leeks, pumpkins, squash and garlic. Mix the chicken manure into the soil in the spring before you start growing your plants. You can buy composted chicken manure in large bags in garden centres as well as in regular grocery stores.

Cow manure

Composted cow manure is suitable for root vegetables, leafy greens and dill that do not need as much nitrogen as e.g. cabbage and squash. You can also grow pumpkins and squash in soil fertilised with cow manure, but if you can also add chicken manure to the soil, it can give it a little extra boost. As with chicken manure, you mix the cow manure into the soil in the spring before you start growing your plants. If you are growing in a pallet collar, we usually recommend filling the pallet collar with a mixture of half cow manure and half potting soil. You can buy composted cow manure in the same places as chicken manure, in large bags in garden centres as well as in regular grocery stores.

Bone meal is long-acting, nutritious and best suited to perennial plants. Bone meal is rich in phosphorus and promotes flower formation, fruit setting and root formation in particular. Preferably fertilise young berry bushes and fruit trees with bone meal, and even flower bulbs when planting in autumn or spring. Bone meal is suitable for organic gardening.

Blood meal is very rich in nitrogen and is particularly suitable for cabbages, lettuces, spinach, leeks and celery. Blood meal is very fast-acting and is best administered in small and repeated doses. Blood meal is also an organic fertiliser made from natural materials and provides a vibrant and healthy soil. It is suitable for use in organic gardening.

You can find bone meal and blood meal in most garden centres.

Liquid plant food for watering
Once the vegetables have grown a few centimetres, it is easier to water them with nutrients in order to provide the right amount of nutrients deep down. You mix the nutrients into the water before watering. The amount to use is indicated on the packaging. Liquid plant food can be found in virtually all garden centres and often in ordinary grocery stores too. Always read the packaging carefully so you know what you are buying and how to use it.

Natural fertilisers

Leaf mulch

Collect leaves in autumn and run your lawnmower over them. Add the mulched leaves to the soil in your pallet collars and garden plots or save in a bag for next year.

Grass clippings

Grass clippings are nutrient-rich and can be used for both mulching and covering soil. Grass clippings will also keep weeds at bay if you put some between the plants, as well as providing nutrients.

Nettle water
Soak the nettles in water and leave them covered to ferment for a week. Stir the mixture every few days so that it is thoroughly combined. After a week, the mixture smells bad, but it’ll give a great boost to your plants! A good rule of thumb is to mix one part nettle water with nine parts water and water your plants with the mixture.

Animal manure

Here are a few extra words about animal manure. This means manure from horses, cows or other animals. A distinction is made between hot composted and fresh manure.

Hot composted manure has decomposed and already given off heat, which means that most of the weed seeds that have passed through the animal’s stomach have died. Hot composted manure is easy to work with as it resembles soil, but it does not contain as much nitrogen as fresh manure as some of this is leached out when the manure decomposes.

Fresh manure contains more nitrogen than hot composted manure and it has not yet given off heat in the composting process. This means it can be used to provide additional heat to plants that need a milder climate – horse manure with straw is preferable here. To create a heating effect, you need to manage the manure in much the same way as you would a compost heap. It must be damp, but not wet, and aeration must be provided to allow the decomposition process to start properly. To get animal manure, it usually pays to ask the nearest horse farmer in the area.

Plan your year’s fertilisation

1. Fertilise the ground in your garden in spring. Add well-composted organic material such as composted chicken or cow manure. Don’t use fresh manure – it’s too strong.

2. In areas with cold winters and deep frost well into spring, it is preferable to fertilise in the autumn. In warmer areas, with mild and rainy winters, it is better to wait until the soil has dried out a little in spring. (anpassa denna punkt efter land) 

3. Sow and plant about two weeks after fertilising the soil.

4. When the seeds have grown a few centimetres, it’s time for more nutrients. At this stage, feeding with nettle water or store-bought liquid nutrients works best. Read the instructions on the package on how to mix the right dose with water.

5. During June and part of July, it is possible to water with added nutrients about every two weeks, depending on what you are growing. If you are growing in pots, you may need to feed the plants every week. A small amount of soil means that nutrients are consumed more quickly.

6. Around mid-July, it’s a good idea to stop applying nitrogen fertiliser to perennials (around midsummer in northern Sweden) to give them time to prepare for winter. Fertilising perennials late in the season can affect their hibernation and frost resistance.

6. Late-harvested vegetables and annual flowers can be fed up to two weeks before harvest because they grow a lot in the last few weeks.

What does fertilise the soil mean?

In spring, fertilise your soil with a nutrient-rich, mould-forming fertiliser which, as well as providing nutrients, improves soil structure and benefits soil microlife. For this purpose, you can use animal manure, grass clippings, packaged hot composted cow manure or compost. You can also combine these fertilisers. The amount of fertiliser to be used is not easy to describe as it depends on the soil already in the containers and in your garden. As a guideline, I usually fertilise a pallet collar with two generous shovels of hot composted horse manure, which is then turned into the soil with the help of a pitchfork.

Complementary fertilisation

As the nutrients in the fertilised soil don’t always cover the need for nitrogen, in particular for some vegetables, more needs to be added in an easily accessible form during the growing season. For example, you can mulch with grass clippings, feed with nutrient water (such as nettle water, organic nutrient solution or chicken manure dissolved in water) or simply mound pelleted chicken manure next to the plants and water. The best way to know if your plants need more fertiliser is to look at them. If plants are stunted, pale and have yellowing leaves that fall off prematurely, they are suffering from nitrogen deficiency. If, on the other hand, they are abnormally green and lush with a large leaf mass, there is an excess of nitrogen and you end up with a vegetable that is not as nutritious, tasty or sustainable as it might otherwise have been.

Remember

When it comes to fertilising plants, it is better to fertilise little and often then abundantly and infrequently. The risk of nitrogen leaching into the environment is minimised and you have time to inspect the plants and see how they are doing. In autumn, stop fertilising completely because the plants won’t have time to take up the nutrients, which also contributes to nutrient leakage, leading to the acidification of our lakes and rivers.

What kind of soil do you have in your garden?

For example, if you have sandy soil, your vegetables may need to be watered a little more often than if you are growing them in loamy soil. Read our tips on how to easily find out if you have sandy or loamy soil in your garden.