Growing Marrows, courgettes, vegetable spaghetti
Cucurbita pepo ovifera
These half-hardy members of the cucumber family are also grown for their fruits which are usually ovoid and cylindrical. There are two types of true vegetable-trailing type and bush type. The former produces long, sprawling stems which are difficult to train while bush marrows have a more compact habit, are more suited to and produce mature fruits about two weeks earlier. The fruit colour is either green, whitish/yellow or striped and the marrows are at least 30cm (12in) long when mature. They may be harvested fresh in summer and autumn and eaten as a boiled vegetable or may be stuffed with meat and spices before baking. They can also be stored for winter use. Courgettes are really baby marrows although special cultivars—such as the Italian Zucchini-have been developed. There are a number of dishes which use 15 to 20-cm (6 to 8-in) long fruits which, if they are left on the plant, will eventually grow into full-sized marrows. Custard marrows have a bush habit and dumpy, round fruits with a scalloped edge. Vegetable spaghetti is trailing and has fruits about 20cm (8in) long which are cooked whole and then sliced open to reveal the spaghetti-like flesh.
Soil and fertilizer requirements
Marrows andneed fertile, well-drained soils. They grow rapidly and require large quantities of water and plant nutrients. The best soils are those which have received generous dressings of organic manure or while the preparations used for ridge can also be used for these crops. Prepare the ridges or mounds in late spring—siting them in sheltered positions — in order to plant in late May or early June. Do not apply base fertilizers, otherwise you will find yourself with a lot of leaves concealing disappointingly little fruit.
Plant raising and planting
Marrow and courgette seed sometimes has poor or erratic germination but if it is ‘chitted’ before sowing plant raising will be more certain. Seed should be sown under protection in late April or early May for planting a month later. Lay two or three layers of blotting paper or kitchen towel on a plate or dish and soak them with water. Scatter the seeds evenly on the surface and keep the container at 18°C/65°F while ensuring that the paper/towel remains moist.
Within a day or two the young roots will appear from some of the seeds; push them carefully to a depth of 3 to 4cm (about 1 – 1-1/4in) into a 9-cm (3-½-in) pot full of compost. Directly the seeds begin to germinate they must be transferred to individual containers. Keep the temperature between 15°-18°C/ 60°-65°F and never allow the plants to dry out. Harden the plants off in a cold frame for a few days before planting. Marrow or courgette seed—dry or ‘chitted’— can also be sown directly outside into the mounds or ridges in mid to late May. Sow one chitted or two dry seeds at each station. Treat as ridge cucumbers. Do not plant outside until all danger of frost has passed, although early protection can be given by cloches or polythene tunnels. Plant bush marrows—including custards—and courgettes, 60 to 80cm (2ft to 2ft 6in) apart with trailing types and vegetable spaghetti 1.5 metres (about 5ft) apart, making sure that plants are well firmed and watered in.
Once marrows/courgettes are established there are likely to be very few problems. Water them generously all around the root zone and conserve moisture by mulching round the stems with organic manure, peat or grass. Bush and custard marrows and courgettes require no training. Stop the stems of trailing plants when 45cm (18in) long to encourage laterals to develop.
Both male and female flowers must be retained since fertilization is necessary.
Usually insects will transfer the pollen, but if cold or very dry weather has discouraged the bees, you may need to hand-pollinate the flowers. Remove a male flower, peel back the petals and push it into—and leave it inside—a female flower. Alternatively pollen can be transferred on a camel hair brush.
Weeds must be removed until the/ courgette leaves meet across the rows. If too much vegetative growth develops it will be necessary to remove some of the leaves.
Cut courgettes when they are 15 to 20cm (6 to 8in) long. This will encourage others to develop. Harvest custard marrows when young to keep the maximum flavour. Pick marrows and vegetable spaghetti as required at 30cm (12in) long. They are best when eaten young and the flesh will be over-mature if your fingernail will not penetrate the outer skin.
Harvesting should be possible from July onwards if plants were transplanted in late May. Marrows which are left on the plant until the end of September will have a well-ripened skin and can be stored in an airy, frost-free place for winter use.
Pests and diseases
These crops are liable to be attacked by the sameas cucumbers.
Fruit colour of marrow and courgette cultivars ranges from dark green, through light green to bright or creamy yellow. Many cultivars have patterned fruits but the flesh is not influenced by skin colour.
‘Long Green Trailing’: dark green with lighter stripes.
‘Golden Delicious’: yellow skins and flesh; good keeper.
‘Smallpak’: high yields of smallish fruits.
‘Early Gem’: F1 hybrid; early and reliable.
‘Prokor’: F1 hybrid; early prolific cropper.