Courgettes (or zucchini) are an easy to grow and highly rewarding plant for both beginners and experts in the garden. Read on for a comprehensive guide on growing courgettes in pots.

Types of Courgettes

Courgettes come in both climbing and bush varieties. This guide will focus on the bush variety as these are ideal for growing in pots and do not need any support. Climbing varieties can be much trickier to grow and do require support.

Sowing

Courgettes are best started off inside as they can be very sensitive to frost. This is best done in late April, although any time between late April and early June would be fine. Two courgette plants will be enough to produce plenty of courgettes for most families although you will want to sow more as not every seed will germinate and you will want to dispose of weaker plants. 

• First fill a 7.7cm (3’’) pot with firmly packed all purpose compost.
• Plant the seed roughly 1.25cm (½’’) deep. Make sure to do this edge on because the large flat seed can collect moisture on its surface which would cause rot.
• Place these pots in a propagator or tray to help them germinate. Ensure this gets plenty of light, a windowsill is an ideal location for this.
• Keep the compost warm and moist but do not overwater.
• Once you see a small shoot you can be certain germination has occurred. This should take between 1 and 2 weeks.
• Once germination has occurred you can remove them from the propagator or tray.

Acclimatising

Before planting in a larger pot outside, the plant will need to be acclimatised or /’hardened off’. There are multiple ways to do this:

Cloches and Cold Frames

The best way would be to use a cloche or cold frame. These allow the plant to slowly get used to outdoor conditions while remaining well sheltered. Keep the plant in a cloche or cold frame for around a week for it to be acclimatised properly.

Without A Cloche or Cold Frame

If you do not want to use a cloche then you will need to gradually move the plant in and outside over the course of a week. Leave outside during the day in a sheltered spot and bring inside during the night. Avoid doing this on cold or windy days as the courgette plant is very sensitive at this stage.

Planting

Once the last frost has definitely passed (this will usually be in early June) and the roots have filled your small pot,  you can move your courgette plants into a large pot (45cm/18’’ diameter minimum). 

• Fill the pot with a mixture of compost and soil.
• Dig out a hole roughly the size of the pot you used to sow the courgette plant.
• Take the plant out of the small pot and place it in the hole, firmly pack the soil around it (here is a good time to add the pot and mulch mentioned later on in the watering section).
• Place the pot in full sun (courgettes love a lot of sun and should get at least 6 hours of sun a day) with around 1m distance between each pot. Courgette plants grow surprisingly large and need space to get ventilation because they will get too damp if packed close together.

How Do You Care For a Courgette Plant?

Young Courgettes

Young courgette plants can be vulnerable to frost, wind and slugs. To protect them from the cold you can use a cloche. To protect them from slugs and snails there are a variety of options such as slug killer and slug tape.

 

Watering

Courgettes need watering on a regular basis to keep the soil moist. You might want to add a layer of mulch on top of the soil to retain this moisture. When watering the plant, avoid watering on to the plant, keep the water at the base of the plant. A handy trick for this is to place a small pot in the soil around the base of the plant and fill that when watering.

Fertilising

Once the fruit has begun to swell, you should feed your courgette plant once every 1-2 weeks with tomato feed or another high potassium liquid fertiliser.

Pruning

Courgettes can be pruned. You might want to do this with the oldest and largest leaves to prevent it covering other plants with shade. You should also remove any sickly or damaged fruits to prevent the spread of mildew or grey mould.

Preventing common problems with courgettes

The following are common problems and solutions you may encounter when growing courgettes:

 

• Not fruiting – a courgette may not fruit if it is only producing male flowers (female flowers have swelling around the base where a young fruit is growing, males do not). It will usually produce only male flowers at first but will begin to produce female flowers after a week or two. If this does not happen it might be a sign that the plant is not getting enough water. A courgette plant will also not fruit if it is not being pollinated. This should happen eventually but you can manually pollinate them by brushing a male flowers stigma and then brushing a female flowers stigma. 
• Grey mould, powdery mildew and rot – these can all happen due to humid and moist weather. Cut away any affected areas and make sure your pots are properly spaced apart from each other.

Harvesting Courgettes

You can harvest the male flowers early on. These are considered a delicacy and can be stuffed, roasted and even deep fried. 

 

Harvest the courgettes themselves while they are young (around 10cm/4’). This will encourage the plant to grow more and you will get less watery courgettes. To harvest, just remove the courgette by slicing it off with a sharp knife.