Radishes

Overview

Radish summer/winter                                       Rotation group – Brassicas

Summer radish need a fertile, moisture holding soil to grow well. They are a quick growing crop only taking about six weeks from sowing to harvesting. Winter radish should not be grown in soil that is too rich; they are best grown as a follow on crop but still within the crop rotation plan.

The spring and summer cultivars have to be harvested and used straight away, the winter cultivars that can either be lifted and used as required or stored in boxes containing damp sand or old potting compost to prevent them from shrivelling. It is better to sow summer radish in short rows about every three weeks to maintain a regular supply of mild, crisp radish.

How to grow

Sow

Summer radish is grown from seed that is sown in short rows between February and the end of May. After this time the temperatures are too high to encourage germination and to produce good quality radish. The earliest sowings have to be made with the protection of a greenhouse or under cloches. The first of the outdoor sowings can be made from mid-March onwards. Delay the unprotected outdoor sowing if the conditions are cold and wet and continue using cloches.

The earliest that the seed for winter radish should be sown is July. Use a Japanese cultivar for this early sowing, the Chinese and Spanish selections will run to seed if they are sown too early in the season. The safest time to sow the seed of winter radish is July in the colder regions and during August in warmer regions. Sow the seed as described below but the seedlings must be thinned to 20cms/8ins apart and then grown on like turnips.

The seed is sown thinly in shallow drills 25mm/1inch deep, watering along the drill with liquid seaweed just before sowing the seed to encourage quick germination and to produce strong, healthy seedlings.

Grow on

Spring and summer radishes are in the soil for such a short time that they don’t need thinning or require too much attention. Birds like to pull them up and leave them on the surface of the soil. This can be controlled using net protection.

Aftercare

Radish must never go short of water at any time during their growing period. Always water well during dry spells including liquid seaweed in the watering can and hoe regularly between the plants to control the weeds and to produce a dust mulch.

How to Harvest

Harvesting

Summer radishes are best pulled when they are young and are not allowed to grow too big. They are best picked when they are between 12.5mm/ ½ “and 18mm/ ¾ “in diameter.

It is best to lift winter radish towards the end of October before the very wet and cold soil conditions arrive. Store the radish in damp sand or old potting compost.

Issues

Pest and disease

Flea beetles are the main pest of summer radish. They are mostly a problem to the young plants under dry soil and weather conditions. Water along the rows in the cool of the evening to create a moist atmosphere around the young plants.

Radish are brassicas and the danger of club root is always a problem. It is important to use crop rotations to prevent the possibility of an attack of the disease.