The use of wood ash as fertilizer has become quite popular and is particularly practical for people who heat with wood. But before you get started and happily spread ashes all over the garden and in the pots, you should know which plants it is best suited for. Additionally, not all ash is the same, so some caution is required, especially if you want to fertilize edible plants with it. Find out whether you can add wood ash to the compost, which plants benefit from it and how exactly you can make potassium fertilizer yourself with this waste product.
Using wood ash as fertilizer – advantages and disadvantages and what you should consider
Is ash good for plants? Definitely. But whether it is suitable for vegetable plants and other edible varieties depends primarily on its origin. Trees store any pollutants from the environment in their wood. For example, if the trees were in an industrial area, the pollutants would also be contained in larger quantities. And precisely because they don't excrete them again, the age of the tree also plays a role, because the older, the more pollutants are stored. So if you use wood ash as fertilizer for the vegetable patch or fruit plants, you should be sure of its origin.
Notice: If you have larger quantities that you want to use, it may also be worth a laboratory test for heavy metals.
Ash fertilizer is suitable for these plants
Otherwise, it is the calcium in the wood ash that is so valuable as a fertilizer. There are also potassium and magnesium, so plants with these nutrient requirements in particular benefit from it. The high lime content is optimal, especially for heavy clay soils, but less so for sandy soils. Accordingly, the alkaline wood ash is suitable for use in plants with high potassium and lime requirements, such as:
- Berry bushes
- Flowering perennials
- Fuchsien
- Geraniums
- Carrots
- potatoes
- Leek
- fruit trees
- Rosen
- Brussels sprouts
- Saddlery
- Tomatoes
- Onions
The fertilizer also proves to be very useful for some plants that are increasingly attacked by pests or diseases. Such sensitive plants include pears, plums, peas, carnations, mallows, fuchsias, roses and daisies.
Useno Wood ash as a fertilizer for plants that require acidic soil. These include, for example:
- Azaleas
- Hardworking Lieschen
- Hydrangeas (but also depends on which flower color you prefer)
- Daffodils
- Orchids
- Peonies
- Palm trees
- Rhododendron
- Rosskastanien
Find out whether wood ash is suitable as lawn fertilizer and how to apply itin this article.
Make and apply the potassium fertilizer yourself
There are various ways to apply wood ash as fertilizer and thus dispose of it usefully. This is how it works:
Apply wood ash directly as fertilizer
Probably the quickest option is to distribute the ashes directly in the bed. All you should keep in mind is to adhere to the non-recommended amount:pro Quadratmeter 300 ml/30 g. That's roughly equivalent to a cup. It is a fast-acting fertilizer that decomposes quickly. That's why the risk of an overdose is quite high. Stick to the recommendation as much as possible.
Alternatively, you can also mix the prepared soil with the ash (e.g. for potted plants). This also prevents an overdose.
Add ash to compost
Since you can use your compost for fertilization anyway, the ash can also be incorporated directly there and then spread out together. This also reduces the risk of over-fertilization. This variant requires a certain amount of preparation time because the wood ash is repeatedly distributed between the individual layers of the compost heap. Since the decomposition of the compost tends to stand still in winter, i.e. during the heating season, this time of year is less suitable for the method.
How can you then use all the fireplace ash that constantly collects? Store them in a dry place in suitable, lockable containers (no aluminum!). Once composting starts again, you can always remove the necessary amount for each layer.
Make liquid fertilizer
Clearly, scattering ashes on a windy day like the first method would not be a good idea. And dry wood ash is also less optimal during dry periods because it requires water to decompose and subsequent watering could wash it away. In such cases, a liquid fertilizer that you use as irrigation water at intervals is very practical. How to make it:
- Take a container (watering can) that is resistant to alkalis.
- Fill them with water.
- Dissolve the cooled ash in it.
- Pay attention to the dosage when fertilizing! You should not distribute more than 30 g of ash per square meter, although over the irrigation water and not directly as a powder.
Only use wood ash as fertilizer!
As already mentioned, not all ashes are created equal. Our contribution only applies to real wood ash from burned wood, but those made from straw or other plant waste can also be used. You should use the following types of ashno wayuse as fertilizer:
- Ashes from treated wood (varnish, glue, etc.)
- aus Pellets
- Paper ash
- Barbecue coal ash
