Crop Rotation in the vegetable garden
In order to sustain the productivity of the vegetable garden over
a number of years we must practice the process of crop rotation. Crop
rotation means growing a set of different crops in a certain area
of the vegetable garden each year. Crop rotation normally follows
a three year cyle where the vegetable plot is divided into three areas
and three different sets of crops are grown each year.
| |
YEAR 1 |
YEAR 2 |
YEAR 3 |
| Area 1 |
Brassicas |
Root crops |
Legumes |
| Area 2 |
Legumes |
Brassicas |
Root Crops |
| Area 3 |
Root Crops |
Legumes |
Brassicas |
Maintaining soil fertility with crop rotation?
The first is that the different vegetable crops we grow have different
nutrient needs from the soil. If we grew the same crop in the soil each
year then the nutrient types in the soil that the particular crop required
would soon be used up. This would lead to progressively declining crop
yields each year. By rotating the crops we can balance the nutrient
demands on the soil so that one particular nutrient set isn’t
exhausted.
Certain crops can actually provide benefits to the soil for one of
the other crop groups. An example of this is the legumes group. The
roots of peas and beans actually fix nitrogen in the soil. Nitrogen
is required for leaf growth and so the Brassica group and leafy greens
are normally planted the in the site of last years peas and beans.
Using crop rotation to aid in pest and disease control
Another important reason for using crop rotation is that it can help
prevent the build up of pests and diseases that occur in the vegetable
garden and will reduce your crop yields by attacking your plants.
The practice of crop rotation is therefore one of the foundations
of organic vegetable gardening as it can reduce the need for chemical
methods of pest or disease control.
If you change the crops you grow each year then plant or plant group
specific pests and diseases (such as Carrot fly) will not have the
same crop to attack the next year. This makes it harder for them to
sustain their presence in the soil.
What vegetables are included in the three different crop groups?
Group 1 Brassicas and leafy greens |
Group 2 Root Crops |
Group 3 Legumes + others |
Cabbages
Cauliflower
Broccoli
Kale
Brussel Sprouts |
Potatoes
Carrots
Parsnips
Swedes
Turnips
Beetroot |
Peas
Beans
Tomatoes
Celery
|