Growing Cucurbits

Cucurbits Growing Guide

What are Cucurbits?

Before we get into how to grow cucurbits, it’s best to understand what they are.

The common types of cucurbits are:

  • Cucumbers
  • Pumpkins
  • Summer/Winter squash
  • Watermelons
  • Muskmelons
  • Courgettes


Many people don’t know that gourds are also included in this group. All cucurbits, except the bottle gourd, have bright yellow flowers. Each vine produces a male and a female flower.

How to grow outdoor cucurbits

Squashes, courgettes, marrows and pumpkins all c have certain characteristics in common, and it pays to know these, to grow them successfully.

What time of year should you plant cucurbits?

These cucurbits have large seeds that you need to soak overnight before sowing.

You can sow these seeds outdoors between May and June, if you want an earlier harvest (July), start by growing them indoors in pots then transplant them outdoors in June.

The seeds usually take 5 days-1 week to germinate.

Growing Cucurbits Indoors

  1. Sow one seed on its side, in seed compost, in a 9cm pot.
  2. Once the seeds have germinated and having produce two or three true leaves, harden off by placing the pots of young plant outdoors by day and bringing them in at night.

Growing Cucurbits Outdoors

  1. Plant the Cucurbits in an area with full sun and ensure the soil is well-draining, to get the best results.
  2. Before planting, prepare the soil by adding organic matter for best results. If your soil is particularly heavy, you can add peat or rotted manure. 
  3. Start by sowing 3 seeds together 3cm deep at stations a meter apart – these plants spread!

How to take care after sowing

As the seedlings start to develop, remove the weaker two, to leave the most robust. The seed leaves and succulent stems of young plants may prove quite a delicacy to slugs and snails so you may consider putting down slug pellets or using organic measures.

For trailing cucurbits pinch out the tips of the main stems when they reach 60cm (2ft). This helps promote side shoots and flowering.

Keep the area well-watered but keep water physically off the leaves and add a mulch around the plants once they have started to flower. At this point you may want to add tomato feed to promote the development of flowers and then fruit.

For pumpkins, grow fewer but larger superiors fruits by limiting the growth to only two swelling fruits per plant. With other cucurbits you can leave a greater number of the fruiting vegetables to swell.

When to Harvest Outdoor cucurbits

For cucurbits, harvest little and often. This promotes a longer cropping season. Use a knife to harvest as opposed to snapping off fruiting vegetables by hand. This produces a clean cut that is less likely to let in pernicious diseases and prevents rashes- courgettes and marrow are quite rough and may cause skin reactions.

Courgettes should be treated slightly differently and be harvested daily otherwise they develop into less intensely flavoured marrows.

Pests and diseases of cucurbits - Cucumber mosaic virus, Root rot, Powdery mildew

Growing indoor cucurbits – cucumbers and melons

Yes, you can grow both these crops outdoors with varieties bred to be hardy in UK conditions. But if you want earlier harvests, you’ll need to grow sweet melons and fresh cucumbers in a greenhouse.

The greenhouse varieties require a bit more TLC than their outdoor-growing counterparts, but melons and cucumbers are both indoor vines and they are things of beauty, producing earlier harvests.

How to prepare the location before planting

Be sure to have the required level of humidity in the glasshouse. You can achieve this by watering the ground early in the morning on a hot day. The vapour will increase the humidity and provide ambient moisture to the stems and roots.

Make sure to feed your vine crops, you can start by adding lots of organic matter or bulky compost to the soil before planting with a helping of general-purpose fertiliser. The soil needs to be rich and fertile, deep and well drained.

Before planting, water the soil well to keep it moist, and warm the soil by covering with a polythene sheet for one to two weeks.

How to grow cucumbers in a greenhouse.

  • Sow the seeds 2cm (3/4in) deep in 8cm (3in) pots between April and May.
  • Transplant young plants into larger pots, grow bags or directly in the soil May to June.
  • Provide support to e plant as it grows.
  • Take care when watering, doing it little and often – do not allow cucumbers to dry out or to become waterlogged.
  • You should pinch out the growing tips when they reach top of their supports. This will help to encourage bushy growth.
  • The cucumbers should be ready for picking about 3 months after sowing and will continue cropping until the end of September.

How to take care of the young plants

Both cucumbers and melons have male and female flowers. The male and female flowers are distinguishable in both fruits, there is either the presence or absence of a small fruitlet at the back of the flower. The female flowers are the one which produce the fruits.

Once the plants have grown to the flowering stage, provide them with a balanced liquid fertiliser to ensure good healthy stem growth as well as good flower formation.

While the plants are growing make sure they have adequate ventilation on hot days, but make sure they don't get too cold on cooler days by closing doors, windows or vents.

How to harvest and take care of the Fruit

When you notice cucumbers and melons start to swell, apply a tomato-feed every two weeks. With melons you may need to apply little ‘hammocks’ to hold the swelling fruits, which otherwise get too big for stems to hold them without support. Cucumbers, which are not so large, don’t require this support.

At the harvesting stage, do not remove fruits from the stems simply by tearing them off. This may damage the stems and create tears that introduce pests and diseases. Cutting the fruits away from the stems with a knife or scissors is a better practice as it helps to keep plants healthy, robust and disease free.

Pests and diseases of vine fruits - Cucumber mosaic virus, Root rot, Powdery mildew, Red spider mite, Whitefly