When to sow radishes?
- Botanical name
- Raphanus sativus
- Family
- Brassicaceae
Radishes are sown outdoors from March to August, 1 cm deep. They germinate in 8 to 10 days. They are harvested from April to September.
Radishes are annual plants. The edible parts are the roots, leaves, flowers and seeds.
Radishes through the year
- outdoor sowing
- harvest
In short
The last frost is not on the same day everywhere, so the recorded weeks are a guide and not a date.
Growing conditions
Companions in the bed
Companion planting is tradition and not an agronomic claim. What is recorded is which pairs sources recommend and which they advise against.
The radish comes up fast and marks the row of the slow carrot. It is pulled before the carrot needs the room.
Kohlrabi is a quick catch crop.
- “Cited” means the pair is named by one source or two.
Pests and diseases
Listed here is every problem for which the sources name this plant as a host. The problems are not listed in order of how common they are.
Cabbage caterpillars
pest- Signs
- The outer leaves of the brassicas have holes eaten into them. The caterpillars and their dark droppings are on the leaves.
- Prevention
- Check the underside of the leaves regularly and pick off the eggs before they hatch. Cover the crop with a fine mesh or fleece, so that the butterflies and moths do not reach the plants at all.
- What to do
- Pick the caterpillars off by hand and remove the affected leaves. Covering with a mesh from planting on is more reliable than picking, because it stops the eggs being laid instead of dealing with the damage afterwards.
Cabbage root fly
pest- Signs
- Transplanted brassicas grow poorly, droop and die, most often in a first wave in late spring. White larvae without legs or head bore into the root collar and the roots. The larvae eat out exactly the edible part of the root.
- Prevention
- Keep to a rotation, because the fly hatches from pupae that overwinter in the soil under the previous brassica. Protect transplanted plants at planting, not at the first sign, because by then the larva is already in the root.
- What to do
- Lay a collar of felt or cardboard around the root collar, so that the female cannot lay her eggs against the stem. A cover of fine mesh that stays on the bed through the whole season is more reliable.
Clubroot
disease- Signs
- The plant lags in growth, the foliage takes on a purple tinge and droops in the heat although there is moisture enough in the soil. The roots are thickened and twisted into club-shaped swellings, and the fine roots are missing.
- Prevention
- The spores stay in the soil for up to twenty years, so rotation is the strongest measure. Return brassicas to the same bed only in the fifth year. Liming raises the pH and lessens the infection, but it does not get rid of it. See to the drainage, on heavy soil with a raised bed, and remove the weeds of the cabbage family.
- What to do
- There is no cure. Raise the seedlings in larger pots and plant them out bigger than usual, so that they outgrow the first infection, and choose resistant varieties. Remove infected plants with their roots and do not compost them. Clean tools and footwear, so that you do not carry the spores onto a clean bed.
Flea beetles
pest- Signs
- The leaves are riddled with small round holes, as if somebody had peppered them with shot. Touched, the beetles jump. Young plants with such leaves stall or die, older ones grow through the damage.
- Prevention
- Clear away the plant debris in which the beetles overwinter. Cover the bed with fleece right after sowing or planting and leave it until the plants are strong. Keep the soil moist, because a dry warm spring is the worst case.
- What to do
- Pin fleece down at the edges, which is the main measure. In autumn or early spring loosen the top layer of soil to cut down the number of overwintering beetles.
Keep track of your plants with Tendask
Log the task and set a reminder for the next one. Every plant keeps its own history, so there is nothing to guess at.
Related plants
The plants below are in the same botanical family (Brassicaceae).
Sources about the plant: Alabama Cooperative Extension System, Bayerische Landesanstalt für Weinbau und Gartenbau, Clemson Cooperative Extension, GBIF Backbone Taxonomy, Iowa State University Extension, KGZS, NC State Extension Plant Toolbox, Royal Horticultural Society, Semenarna Ljubljana, Smernice za strokovno utemeljeno gnojenje (Mihelič et al., MKGP 2011), Utah State University Extension, Washington State University Extension, Wikidata. Checked between 14 and 28 August 2026. The problem descriptions also draw on: EPPO Global Database, University of Maryland Extension.