When to sow cucumbers?
- Botanical name
- Cucumis sativus
- Family
- Cucurbitaceae
Cucumbers are sown outdoors from May to June, 2 cm deep. They germinate in 7 to 14 days. They are harvested from July to October.
Cucumbers are annual plants. The edible part is the fruit.
Cucumber is not sown into pots too early, because the plant outgrows the pot before the ground is warm enough for transplanting. Plants and seed go into the bed at the same time, because soil temperature settles both.
A cucumber is trained up a support or left to trail over the bed. On a support it is set closer together and the rows can be narrower, because the plant does not take up ground.
Cucumber needs evenly moist soil and water every day in the heat. If water runs short, the fruit comes out bitter and bent.
Cucumbers through the year
- indoor sowing
- transplanting
- 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
Are cucumbers toxic to cats and dogs?
No. Cucumbers are not toxic to cats and dogs.
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.
Next to cucumbers the neighbours go to the edge of the bed.
Next to cucumbers the neighbours go to the edge of the bed.
Kohlrabi is a quick catch crop.
Next to cucumbers the neighbours go to the edge of the bed.
The sunflower as a living support. It works only if it is sown a few weeks earlier.
- “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.
- Signs
- Colonies of small aphids sit on the shoot tips and the underside of the leaves. The leaf curls and puckers, and sticky honeydew is left on everything below. The viruses they carry are more dangerous than the feeding itself.
- Prevention
- Go easy on nitrogen, because soft sappy growth is what aphids are looking for. Encourage the predators (ladybirds, lacewings, parasitic wasps). Use a reflective mulch, which puts them off settling, and a strong jet of water to knock the colony off the tips.
- What to do
- Potassium soap works on contact and only while it is wet, so it has to reach the underside of the leaf. On drought-loving plants and in heat it can scorch, so apply it in the evening.
- Signs
- A white, floury coating spreads over the leaves, first on the lower and older ones. The leaf under it yellows and dries up. The fruit stays small, because the plant loses leaf surface.
- Prevention
- Plant resistant varieties, leave an airy spacing and sun, and clear the debris at the end of the season. Unlike most fungi it is not helped by wet foliage, since it spreads in heat and high air humidity, in a dry summer too.
- What to do
- Oil products meant for powdery mildew on the squash family work on contact. They do not cure a leaf that is already affected, but they stop the spread to healthy ones. On herbs cut the affected shoots back instead, since the new growth comes clean. On ornamental perennials what is left is spacing and moisture.
Check the registration and the label before use.
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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 (Cucurbitaceae).
Sources about the plant: ASPCA Toxic and Non-Toxic Plants, Bayerische Landesanstalt für Weinbau und Gartenbau, Clemson Cooperative Extension, GBIF Backbone Taxonomy, KGZS Zavod Ljubljana, KGZS Zavod Nova Gorica, NC State Extension Plant Toolbox, Royal Horticultural Society, Semenarna Ljubljana, Smernice za strokovno utemeljeno gnojenje (Mihelič et al., MKGP 2011), Utah State University Extension, Wikidata. Checked between 14 and 28 August 2026. The problem descriptions also draw on: KGZS, UF/IFAS Extension, University of Maryland Extension, University of Wisconsin-Madison Division of Extension.