Although considered to be a vegetable, courgettes - otherwise known as zucchini - are actually the immature fruit of a marrow squash – more specifically, the swollen ovary of the female flower. Courgettes can be yellow, green or light green, and generally have shape similar to a ridged cucumber, although there are a few cultivars available that can produce a rounded or bottle-shaped fruit.
Like all summer squash, courgettes can trace their ancestry back to the American continent, however the varieties of squash typically known as ‘courgette’ were actually developed in Italy - many generations after their introduction from their country of origin. The first records of courgettes in the United States date back to the early 1920s - almost certainly brought over by Italian immigrants.
How to start courgettes off indoors
In order to achieve an early crop - and yet have protection against late, spring frosts - courgettes can easily be started off indoors. Courgette seed can be sown any time from mid March through to late May. Using a good quality soil-based compost such as John Innes ‘Seed and Potting’, fill 3 inch pots to within ½ inch of the top of the pot. Sow two seeds per pot – on their sides - placing each seed ½ an inch deep.
Temperature is important when it comes to germinating courgette seed and so once they have been watered in they will need to be placed in a warm, bright position at a temperature of between 65 to 70 degrees Fahrenheit. Alternatively they can be placed in a heated propagator.
Once the seedlings emerge, the weaker one can be removed from each pot. Harden off the young plants by putting the first sowing into cold frames at the end of May. Plant them out after about two or three weeks once the risk of late frosts have passed.
Remember to water the pots well before planting out, and avoid holding the plants by their stems as they are easily bruised causing irreparable damage.
If the weather is cool, cover each plant with a cloche for the first week or so, to give them a little extra warmth and protection. Alternatively, use half of a clear plastic 5 litre mineral bottle. Cut the bottle into two halves in order to make two excellent cloches. The top half - whilst giving good protection against the weather – will also allow air and moisture to circulate through the neck of the bottle.
TOP TIP. To prevent flying insects entering through the neck of the bottle, cover with a small piece of fleece and secure it in place with an elastic band.
How to start courgettes off outside
Courgettes prefer heavier soils, and will always do best in a sunny, sheltered position - away from cold winds. When it comes to preparing the ground, it is well worth adding plenty of well rotted farm manure before hand – in fact, this can be done as early as the previous autumn.
.If you intend starting early, you can protect an early planting with cloches. It is a good idea to put your cloches in place where you plan to plant your courgette plants a couple of weeks before you need them as this will to help warm up the soil below. Doing this will greatly increase your early planting chances of success.
.If you are going to sow your courgettes from seed directly into the ground then you can do this any time from early May onwards – around about the time of the last late frosts. With cloches you can sow courgette seed up to three weeks earlier.
The trouble with courgettes is that they like lots of moisture around the roots, but ironically the plants can rot off if there is too much moisture around the base of the plant. To try and overcome this, courgettes are often grown on ridges in order to improve drainage – how to make a courgette ridge is outlined as follows.
.Begin by digging a small trench about 4 inches deep, then fill the bottom of this trench with well-rotted farm manure until the trench is refilled back to its original soil level – now dig over the trench so that the compost and soil is nicely mixed. Now dig a second trench next to this first one placing the soil along to top of the original trench so that you a have formed an elongated mound. This will form a ridge into which the courgette seeds can be planted into - 3 ft apart. Alternatively, if you are only growing a few courgette plants, just make one individual mound per plant roughly 1ft 6in square. These mounts do not need to be too high - no more than a few inches at most.
When sowing courgette seed outside, sow two seeds per planting position – covering with ½in of soil. Each planting position should be about 3 ft apart. When the seeds have germinated they can be thinned out by removing the weaker of the two vigorous seedlings. If you are transplanting courgette seedlings, then they should be planted into the ridge at the same depth as they were in the pot.
Courgettes require plenty of water so that they are able to grow and fully develop so soak the roots thoroughly and regularly. However, try to keep as much water as you can away from the foliage to help prevent the incidence of fungal infections.