How to grow Courgettes

How to grow Courgettes

As they originated in Mexico’s warm climate, it will come as no surprise that these plants need a sunny, sheltered position in order to ensure the best possible growth when growing courgettes in the UK. The soil should be fertile, moisture-retentive yet free-draining. They are heavier feeders than most other crops, so the richer the soil the better their performance will be.

Thankfully, even the poorest spot can be prepared to provide suitable conditions. The best way to do this is to dig out a 30cm square hole to one spade’s depth where each plant is to be positioned. Space the holes at least 60–75cm apart. Fill the bottom third of each hole with well-rotted manure or garden compost and then backfill with soil.

Do this at least two weeks before planting or sowing to give the soil enough time to settle back down. Don’t worry if you’re left with a mound over each planting hole – this won’t pose a problem and will reduce on its own with time.

Alternatively, dig out your planting holes in late autumn and line them with old cardboard. Infill the holes with compostable material, such as kitchen waste, as you produce it. When the holes are a third full, backfill with soil. These ‘compost pits’ of raw organic matter will feed the hungry plants.

How to grow courgettes from seed

Seeds can be sown directly into their final planting position or under cover for extra warmth. If slugs are a problem in your area, then start off seedlings indoors or in the greenhouse to give the plants a head start and reduce the chances of an early attack. When to plant courgettes outdoors? May and June are the ideal times for direct sowings, as the risk of frosts should have passed.

Raising seedlings under cover is generally more reliable as the conditions can be monitored to give a steady, even growth rate and strong young plants. Sow two seeds into 7cm pots of multi-purpose compost. Water these and place them in a propagator to germinate or onto a warm windowsill.

The seedlings will push their way through in as little as a week. Sowings under cover should be made around one month before the last frost, from about mid April to early May, so the seedlings will be ready to plant out once the weather has improved.

If you opt to sow the seeds outside, wait until any danger of frost has past – late May in the south and up to early June further north. Warm the ground with cloches, if possible, or use clear plastic drink-bottle halves placed over the soil to create a mini greenhouse (these are also great for keeping slugs at bay). Push two seeds about 2cm into the soil, edge side down, and water them in.

Growing courgettes from seed isn’t the only option, though - you can get good-quality seedlings from reputable garden centres.

Courgette plant care

Once the fat-leaved seedlings have emerged allow them to grow on for at least two weeks before removing the weakest and leaving a single plant in each pot or planting position. The young seedlings will soon go on to form their first adult leaves.

Keep cloches or plastic bottle-halves over outdoor seedlings in these early stages to encourage strong growth while the weather continues to warm up. You might ask ‘what does a courgette plant look like?’ - these plants can be compact or large, depending on the variety, with big green leaves.

Pot-raised seedlings should be transferred to larger, 12cm-diameter containers as soon as roots begin to poke out from the bottom of the drainage holes. Use multi-purpose compost and keep them in a bright position at a minimum temperature of 15°C. Begin to harden the young plants off about two weeks before planting out time. To do this, place them outside for increasingly longer spells and during milder nights to toughen them up.

When to plant out courgettes

To plant, simply remove them from their pots and carefully lower them into planting holes at the same depth they were at within the pot. Courgettes can also be cultivated in grow bags, but you will only be able to place two per bag and they will need far more watering than crops such as greenhouse tomatoes grown in the same way.

If you are wondering when to plant out courgettes, it is best to wait until the last of the hard frosts have passed - any time after late spring is usually a safe bet.

Courgette plant spacing will be important - check the height and spread of your chosen varieties, but they will need plenty of room to grow on, and can make quite a size. If you are short on space, it is possible to start growing courgettes vertically, but again, make sure your variety is suitable for this. One of the benefits of growing in this way is that the resulting fruits will be much easier to harvest!

To help with watering, insert a plastic pot, open side up, into the soil close to the stem of the plant. Your water and liquid feed can be poured into this pot, which will dispense it in a controlled flow from its drainage holes.

Another option is to bank up the soil in a 5cm ridge around the edge of the planting position to create a reservoir which will be flooded during watering. This will stop the water running straight off the surface of the soil, and is particularly useful for soils that can bake dry and hard.

Apply a mulch in hot weather to lock in the moisture and keep weeds down. Garden compost, grass clippings or manure will all work, but be sure that the mulch does not touch the stem of the plants or the concentration of nutrients could harm them.

Although these can be large plants taking up a fair amount of space, it is possible to continue growing courgettes in pots - but do make sure you choose a variety suitable for this kind of cultivation.

If you are looking for a good companion plant courgette, they grow well with sweetcorn, borage, beans, marigolds and nasturtiums - to name just a few!

Towards the end of the season some of the leaves may take on a dusty grey appearance. This is the fungus powdery mildew and although it isn’t ideal, in small doses it does little to affect the productivity of plants. Good levels of water will help keep this to a minimum as plants will grow stronger.

In nutrient-rich soils that have been further enriched with manure and compost there will be little need for extra feeding during the growing season, but on sandy soils plants will benefit from an organic liquid feed, such as comfrey tea or liquid seaweed, every two weeks.

You might have asked the question ‘do courgettes grow into marrows’? And the horticultural answer is, technically, no. They are different members of the family - although, courgettes that have been left to grow large on the plant are often referred to as marrows.

Once you harvest the first courgettes keep picking them, as this will ensure the plants continue producing fruits. Thoroughly check over each plant at least three times a week and cut off the courgettes using a sharp knife. Hold the fruit with your hand while removing it and do not tug at the plant.

The plants have both male and female flowers. Male flowers tend to appear a little earlier than female blooms. The latter have a slight bulge immediately behind the flower (this is the embryonic fruit). The earliest male flowers can be fried as above and will offer a tantalising glimpse of the bounty to come.