Our Essential Guide: How To Grow Courgettes & Squash

Our Essential Guide: How To Grow Courgettes & Squash

The good news is that these are really easy to grow. The temptation is to grow too many plants, and to end up with a tsunami of courgettes and squash in the summer and early autumn. So unless you like eating courgettes three times a day limit yourself to one plant per adult in your household. You will still have loads! Likewise with squash, if you are growing more than one variety (there are lots: different colors, sizes, shapes, flavor, keeping qualities) then just grow one plant of each. You may want to sow a few extra seeds just in case they don’t all germinate, but make sure you then give some of the plants away to friends and neighbors (or leave them outside your gate – they will quickly disappear to a good home). You will be amazed at how good your freshly harvested veg taste and you’ll never want to buy an insipid supermarket courgette or squash again.

Growing Courgettes From Seed

You can sow the seed straight in the ground in late May or early June with a cloche on top for a few weeks, but the easiest thing is to sow the seed indoors in April or May. Sow the seeds on their side 13mm deep in 7.5 or 9cm pots of compost. Keep in the greenhouse or on your windowsill until late May when you will have at least two sets of leaves.

Planting out

  1. Two weeks before planting out make a planting hole, allowing for 90cm between plants. The hole should be a spade’s depth and width. Fill the hole with well-rotted manure or compost and add a sprinkle of general fertilizer on top. Water well.
  2. Next you need to Acclimatize your plants to being outside. A week before planting them in early June you need to put them into a cold frame, or bring them outside during the day, inside overnight for a week, then leave in a sheltered spot for another week.
  3. Finally, plant one plant per hole and water well.

Caring for Courgettes and Squash

  • These are thirsty plants, but make sure you don’t water the leaves, and don’t soak the plant too close to the stalk or it may rot.
  • Feed with a high potash liquid feed (such as a tomato feed) every 10-14 days once the fruits appear.


You don't need to buy specialist feed for all your different veg and flowers. Commonly sold tomato feed will do a fabulous job for anything that wants lots of potash (potassium-rich salt mineral).

Squashes and marrows

Saving Seed

It is easy to save seeds from both courgette and squash, though you will need to leave a courgette to get bigger than you would normally to ensure the seeds are well developed. Scoop out seeds, rinse in running water in a sieve then dry on kitchen paper and label before storing in a cool dry place over winter.


  • Powdery mildew appears as a white powdery deposit over the leaves and they start to shrivel and become stunted. Keep the soil moist to avoid this.
  • No fruit or fruit rotting when small. Usually a temporary problem caused by the weather being too cool in early summer, resulting in poor pollination.
  • gray mold appears as gray, fuzzy fungal growth which may start off as pale patches. This is usually the result of damp, humid weather. Remove any affected parts of the plant immediately and burn (the spores may otherwise survive over winter).

rhino greenhouse courgette plants in foreground in raised bed

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