Capsicum annum


Common name: Sweet Peppers

Sweet peppers can range in colours from green to yellow to red depending on the stage of ripeness.

Similarly they can come in various shapes, sizes for example; carrot shaped, bell shaped or block shaped.

They can be eaten cooked in stews, stir fries and or raw in salads.

Corno de Rosso
Purple Beauty

They are not fully hardy and should only be grown outdoors in the south and west of the UK. i.e. in areas where the temperature does not drop below 12°-15°C (55°-60°F)

In the cooler northern areas, they can be stood outside in pots during the summer and brought indoors when the weather becomes much cooler.

Otherwise, plant them out 600mm (24") apart in a cool Greenhouse border,Tunnel, Growbags, Large pots or Ring Culture.

Depending upon variety, they will grow to a height of 750mm (30")

Aim for a minimum night temperature 15 °C (60 °F), and avoid temperatures above 30°C (85°F) under glass, by providing maximum ventilation.

Avoid starting pepper plants too early in the spring this practice can lead to leggy plants that may never fully recover.

Pests and Diseases:


The main three pests that can affect sweet peppers are thrips, whitefly and red spider mite, all of which can be controlled biologically or by proprietary insecticides.

Regular misting will deter spider mite, and aid fruit set.


Aphids, snails and slugs can be troublesome.

As with tomatoes, peppers are sensitive to temperature fluctuations, which can cause bud drop or poor fruit set.

Similarly, irregular watering or dry compost can cause blossom end rot.

Affected fruits show a leathery pale brown patch at their base, pick off affected fruits to encourage new flowers.

Blossom End Rot

Adequate staking to support the heavy fruit is important to avoid branches breaking, particularly with plants grown outside that are subject to winds.


Week 11:

Sow seeds in pots / trays of seed compost and germinate at a temperature of 21°C (70°F)

Germination should take around 10-12 days

Sweet Pepper Seeds
Germinated Seedlings

Week 13:

When the seedlings are large enough to handle, prick them out individually into 75mm (3") pots of potting compost.

Pricked out Seedlings
Seedlings Growing-on

Week 18:

If planting out is delayed perhaps because of the weather, pot up plants into 125mm (5") pots rather than letting them becoming potbound in the smaller pot.

Week 21-22:

Greenhouse / Tunnel Border method:

Planted Out
Supports in place
Fruit Forming

Ring Culture Method

Planted Out
Supports & Watering facility in place
Fruit Forming


* This task is optional, i.e. with some of the taller varieties this may not be required due the amount of fruit they produce naturally.

Encouraging plants to produce more fruit may give you the desired quantity at the expense of quality.

The reverse is generally true for low growing varieties.

Week 27:

From now on give a dilute liquid feed (potash) at two week intervals when the embryo fruits appear.

Continue feeding up until the fruit changes colour.

If grown under glass, lightly shade the glass during the hottest months.

A hint of colour change
Trace of red colouring
Half ripe
Ripe fruit

Week 34 onwards:

The fruits should be ready for picking in September / October depending upon variety and season.

Harvested Fruit

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