have horrible clay soil in my garden that always seems to be soggy.
How can I improve the drainage of this soil?
soils can be improved by adding organic matter, such as manures
and compost, and calcium in the form of gypsum or calcium sulphate.
There is a simple test
you can carry out to ascertain whether you need to add calcium to
your soil or not.
Put about 2 cm of soil
in a large jar, fill it with water, screw on the lid and shake thoroughly.
If the water clears within half an hour you will not need to apply
any calcium. If it takes one to two hours for the water to clear,
apply about 50 g of calcium per metre squared to your soil to improve
drainage and structure. If the water has still not cleared after
several hours, add about 200 g per metre squared to your soil, digging
it in at least 30 cm deep. Repeat this process every four weeks
until new tests show soil improvement.
Spent mushroom compost
is an excellent mulch for clay soils because it is high in calcium.
As mushroom compost can be very alkaline, however, avoid applying
to alkaline soils or where phosphorus-sensitive plants, such as
proteas, banksias and grevilleas, are planted.
by Dr Dan Blanchon from Unitec's Diploma in Sustainable Horticulture and Bachelor
of Resource Management.
with permission from NZOOM Home and Garden content,
from the previous
The views expressed here are not necessarily those of the RNZIH