Q&A: Is weedmat necessary under fruit trees in a home orchard?
Question: How do I feed my miniature peach, apple, nectarine and feijoa trees? The ground is completely covered with weedmat. What fertiliser do they need and what time of year should I feed them?
Answer: As you've found, weedmat creates a barrier that makes it difficult to add fertiliser and organic matter to the soil.
It can also reduce the amount of water and oxygen reaching the root zone so the trees may not reach their full potential. On the plus side, careful use of weedmat reduces rampant grass growth that can swamp small trees.
Consider replacing the weedmat with a generous layer of mulch which will add nutrients and humus to improve the soil as it breaks down, and also suppress weeds and retain moisture. Keep the mulch from touching the trunks as this may cause rot.
Sheep pellets and compost improve soil fertility and gypsum makes clay soils more friable.
An understorey of flowering plants adds interest, attracts pollinating insects, increases diversity and reduces run off and leaching of nutrients. Plants such as comfrey with long tap roots bring up nutrients from the subsoil.
Feed pip and stone fruit in summer and autumn. Use a balanced fruit fertiliser with nitrogen and potassium for leafy growth and fruit production, and magnesium to avoid diseases caused by soil deficiencies.
Feed feijoas with general fertiliser in spring and again in summer.
- NZ Gardener