This document discusses methods for extending the outdoor growing season for vegetables, including using protection like cloches and tunnels. It describes propagation methods like direct sowing, seed beds, and planting young vegetable plants. It also discusses crop rotation systems using four groups (legumes, brassicas, alliums, roots), the benefits of rotation in minimizing pests and helping successive crops, and limitations like personal taste preferences. Successional cropping through staggered plantings and crop varieties is described as well as intercropping, mixed cropping, and "cut and come again" vegetables that regrow after harvesting.

1. RHS Level 2 Certificate
Week 19 – Outdoor food
production. Vegetables –
crop rotation, intercropping
and successional cropping

2. Learning outcomes
 1.1 Describe the methods used to advance and extend the productive
season of outdoor food crops; including the use of polythene, mulches,
fleece, ‘enviromesh’, low tunnels, cloches and cold frames.
 1.2 Describe propagation methods used in the production of vegetable
crops, including direct sowing and raising plants in seed beds, blocks
and modules
 2. Crop rotation etc
 2.1 State the benefits and limitations of using crop rotation.
 2.2 Describe a four-bed system of crop rotation.
 2.3 Explain how successional cropping can be achieved for a NAMED
crop by using sowing and planting dates, choice of cultivars and
environmental protection.
 2.4 Explain how intercropping can be used to maximise production.
 2.5 Describe the effect of plant spacing on a named crop.
 2.6 Describe what is meant by ‘cut and come again’ vegetables

3. Extending the season for food crops
 Using protection – cloches, greenhouse,
poly-tunnel - at the beginning and end of the
season.
 Using varieties that are suited to the stage of
the growing season. For example Peas
(Pisum sativum) can be picked from May to
September if the right varieties are chosen.
 Sow in succession – so that there are new
plants ready to harvest as one batch finishes.

4. Successional cropping
 Sowing different varieties – early, mid-
season and late
 Sowing a few seeds at regular intervals so
that the plants do not all reach maturity at the
same time. For example, hearting lettuce
(such as Cos) take 8 -14 weeks to reach
maturity. Sowing half a row each week-10
days from late March until late July gives
continuity of harvest May to October.

5. Propagation methods for vegetables
 Seed – sown outside or sown in pots under cover.
Modules or soil blocks to minimise root disturbance.
Seed beds for brassicas that will be transplanted.
 Plants – young vegetable plants at planting out stage
can be purchased from mail order suppliers who will
deliver in the correct week for planting.
 Roots, slips and sets – Asparagus (Asparagus
officinalis) is supplied as a root, Sweet potatoes
(Ipomoea batatas) as slips (shoots with part of the
root tuber – a bit like propagating Dahlia) and onions
(Allium sativum) as sets (juvenile bulbs).

6. Intercropping and other intensive
cropping approaches
 Intercropping – growing rows or plants of a quickly
maturing vegetable between those of a slow growing
one.
 Catch cropping – growing a quickly maturing crop on
soil left vacant by a harvested crop or set aside to be
planted later.
 Mixed cropping – growing several vegetables
together that benefit each other and are harvested at
the same time (e.g. ’the Three Sisters’: sweet corn,
beans and squash).

7. ‘Cut and come again’ and ‘baby’ veg.
 Cut and come again – takes advantage of the fact that
leafy vegetables will re-grow if the growing point/roots
are not removed by harvesting. Either involves
removing a few leaves at a time or harvesting the head
and stimulating re-growth.
 ‘Baby’ vegetables – quick maturing cultivars sown at
close spacings so that the competition encourages
smaller plants that grow rapidly to maturity and can be
harvested small and early.

8. Crop Rotation – basic principles
 Three or four groups (excluding permanent
planting) depending on plot size. More groups =
longer cycle (the longer the cycle the better).
 Four group cycle – legumes, brassicas, alliums,
roots. (For a three group – put alliums with
roots).
 Legumes are generally followed by brassicas.
 Root crops (include potatoes if space does not
permit a separate area) tend to be followed by
alliums (the cultivation required for roots
minimises weed competition).

9. Crop rotation – rotation groups
 Vegetables divided into five groups –
permanent planting (perennials like
Asparagus); Brassicas; Legumes; Alliums;
root crops.
 Salad crops and some others like Sweet
Corn and squash do not fall into a rotation
group
 The principle is not to grow the same group
on the same soil two years running.

10. Crop Rotation – benefits and
limitations
Benefits Limitations
Minimises plant problems
– pests, diseases and
deficiencies
Most pests and diseases
are mobile or have long
persistence
One crop can benefit the
next in the rotation –
nitrogen fixing legumes;
potatoes suppress weeds
Personal taste is vital on a
small scale – the grower
might like brassicas but
not carrots.
Planning the rotation also
enables planning
succession
Inflexible – intercropping,
catch cropping or mixed
cropping do not fit well

11. Learning outcomes
 1.1 Describe the methods used to advance and extend the productive
season of outdoor food crops; including the use of polythene, mulches,
fleece, ‘enviromesh’, low tunnels, cloches and cold frames.
 1.2 Describe propagation methods used in the production of vegetable
crops, including direct sowing and raising plants in seed beds, blocks
and modules
 2. Crop rotation etc
 2.1 State the benefits and limitations of using crop rotation.
 2.2 Describe a four-bed system of crop rotation.
 2.3 Explain how successional cropping can be achieved for a NAMED
crop by using sowing and planting dates, choice of cultivars and
environmental protection.
 2.4 Explain how intercropping can be used to maximise production.
 2.5 Describe the effect of plant spacing on a named crop.
 2.6 Describe what is meant by ‘cut and come again’ vegetables