October 5, 2022, 8:53 am | Read time: 4 minutes
A hedge can be fertilized with potassium in the fall to make it hardy for winter. However, there are some things to consider. Otherwise, the plants risk being over-fertilized.
Plants need many nutrients to grow. Hobby gardeners can promote growth and plant health with a dose of fertilizer. Slow-release fertilizers generally help in the spring. This also applies to hedges. However, you can also pamper them with some fertilizer in the fall to make them winterproof. Special potassium fertilizer is suitable for this. myHOMEBOOK explains how to use potassium fertilizer correctly.
How do I know if my hedge needs potassium?
You can recognize a potassium deficiency by the yellowing and browning of the hedge leaves at the edges, curling, and dying. If nothing is done, the hedge can quickly perish.
What is potassium fertilizer?
Potassium is a so-called macronutrient, like nitrogen and phosphorus. To thrive, plants need large amounts of these three main nutrients. While nitrogen promotes growth and phosphorus supports flower and seed formation, potassium is important for plant health. The nutrient strengthens plant tissue and promotes root and tuber formation. Potassium also inhibits water loss, regulates water balance, photosynthesis, and metabolism. A dose of potassium helps plants during drought or frost.
The nutrient is sufficiently present in many soils. However, to unleash its effectiveness, microorganisms, called microbes, must convert the substance for plant uptake. If your garden soil is not in good condition, you should supply your hedge with potassium-rich fertilizer.
Potassium fertilizer, also called potash fertilizer, can consist of various ingredients. Potassium-rich fertilizers made from potassium magnesia or patent potash, wood ash, or even algae are often found in stores. Manure from poultry, pigs, and cattle also contains a high amount of potash. Bone meal also has a lot of potassium.
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When should I fertilize the hedge with potassium?
Ideally in late summer or fall. This increases the hedge’s winter hardiness. To promote growth, you should fertilize the hedge in the spring before new shoots appear. However, not with pure potassium fertilizer, but with commercial hedge fertilizer or mature compost. Specialized fertilizers tailored to specific hedge plants are also available in stores.
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How do I fertilize the hedge with potash?
If you are planting the hedge anew, mix potash fertilizer into the planting soil. Apply liquid fertilizer with the watering can to the base of the hedge plants. Spread granular potash fertilizer on the soil. Be sure to follow the manufacturer’s instructions.
Can I over-fertilize the hedge with potassium?
Yes. Too much of a good thing can have the opposite effect. Over-fertilizing your hedge with too much potassium can lead to a deficiency of lime and magnesium in the soil. Then the hedge hardly grows in height.
To prevent over-fertilization, it is recommended to conduct a soil analysis every three years. This way, you know whether and what nutrients are lacking or in excess in the garden soil.
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What does potassium fertilizer cost?
Inexpensive liquid potassium fertilizer is available in stores starting at around 10 euros per liter. This is usually enough for 15 to 30 linear meters of hedge. For two kilograms of potash fertilizer in powder or granular form, you currently have to pay around 13 euros in specialty stores.
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Can I make potash fertilizer myself?
Yes. It’s quite easy to make with a homemade plant slurry. Bracken, comfrey, or dandelion are well-suited. myHOMEBOOK explains how to make the slurry in this article.
You can also make potash fertilizer from wood ash. Where do you get it? Just use the leftover ash from the fireplace. Mix the ash with some water and apply the liquid fertilizer to the hedge plants.
Is potassium fertilizer dangerous?
No. Commercially available potash fertilizer is harmless to humans and animals.