Fertilize thuja - a sense of proportion is required

Fertilize thuja - a sense of proportion is required

When is it necessary to fertilize thuja?

Thuja prefers loose soil that shouldn't be too rich in nutrients. Therefore, you should never overdo it with fertilizing. If you use fertilizers from the garden center, be sure to follow the instructions and reduce the dosage a little. Under no circumstances should you give more than stated on the package.

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Fertilization is only really necessary for very young plants. Even if the hedge looks a bit meager or has yellow and transparent needles, fertilizing can be helpful.

Fertilize the first time

If you have bought thuja in a bale and planted it, do not fertilize at all in the first year. These plants are already adequately supplied with nutrients.

With bare-root thuja, wait two to three weeks with the first fertilization. Then new fine roots have already formed that are able to absorb the fertilizer.

The right time of year to fertilize thuja

It is best if you fertilize the arborvitae in spring. Long-term fertilizer is recommended for this. Later in the year you can do another fertilization in late summer. In autumn or the cold season you should no longer fertilize, as the new shoots stimulated by the additional nutrients no longer harden sufficiently before winter. The shoots then freeze to death in cold winters.

Fertilizer for the tree of life

  • Coniferous fertilizer
  • compost
  • Horn shavings
  • Blue grain
  • Epsom salt

Special fertilizer for conifers that is well suited for thuja is available in stores. It is often offered as a liquid fertilizer. This application form is the simplest and can be distributed very evenly.

Blue grain is also often recommended. In the case of blue grain, however, it is important to ensure that the fertilizer has to be administered about 14 days before the new shoot, as it needs until it reaches the roots of the tree of life. Blue grain fertilization must be done twice a year if it is to help.

You can't go wrong with giving thuja ripe compost or ripe manure in the spring and carefully working it lightly into the soil.

How to properly fertilize thuja

Whatever fertilizer you give, make sure the soil is moist. In an emergency, first walk the floor with the watering can. The fertilizer works faster on moist soil and does not burn the fine roots as quickly.

Follow the dosage instructions. With blue grain you need around 50 grams per square meter.

After fertilizing, water the thuja hedge with the watering can. As a result, the nutrients are released faster and can penetrate the soil better.

When thuja turns yellow

If the tree of life turns yellow, over-fertilization cannot be ruled out. Due to the oversupply of nutrients, chlorosis develops, which causes the needles to discolour.

The main risk of over-fertilization arises from artificial fertilizers that have not been properly dosed.

Under no circumstances should this fertilizer come into contact with the needles, as they will burn them.

Recognize and treat magnesium deficiency

A light discoloration of the needles of the tree of life often indicates a lack of magnesium. Appropriate fertilizers are available in stores. Epsom salt is often recommended for this. If you are not sure whether you really have a magnesium deficiency, seek advice from a specialist.

Improve the soil while planting

In the first two years after planting, you do not need to fertilize thuja at all if you have prepared the soil well beforehand.

To do this, loosen it up deeply and remove all thickenings, stones, roots, etc. Mix the potting soil with ripe compost, deposited manure and / or horn shavings. (€ 6.39 at Amazon *) Then the roots have enough nutrients available right from the start.

Peat is also suitable for improving the soil, but should only be used in an emergency for ecological reasons.

Fertilize with mulch blankets

The best way to provide thuja with sufficient nutrients is to create a mulch layer under the hedge. With this method you avoid over-fertilizing the tree of life. Suitable mulch materials are:

  • Lawn cuttings (without seeds)
  • Foliage (only healthy leaves)
  • chopped leftovers of thuja
  • Bark mulch
  • straw

Applying a mulch layer has the additional advantage that the soil moisture is kept constant because the water does not evaporate as quickly. In addition, the mulch (€ 213.00 at Amazon *) keeps weeds away and saves you a lot of work.

The mulch cover is ideally laid in spring every year and renewed in autumn if necessary.


Do not fertilize thuja with fresh compost or manure. Only use mature fertilizer material because on the one hand there is a risk of over-fertilization and on the other hand the roots can burn.