Make the most of your Cucurbits

Cucurbits are members of the Cucurbita pepo plant-family. Cucumbers, zucchinis, pumpkins, squash, marrows and melons are all cucurbits. They all need very similar soil and climatic conditions and need to be treated in much the same way to be a success.

Cucurbits love warmth and sunshine. They hate cold conditions. Frost ruins cucurbits. In Tasmania grow cucurbits in the most sheltered spot in your garden, or better still, grow them in a hothouse.

Cucurbits are big eaters, so add plenty of compost to soil where you are going to plant them. Put some COF (complete organic fertiliser) or similar in their planting hole when planting out seedlings. Regular foliar feeding with organic liquid fertilisers will also make a big difference.

Cucurbits are easily affected by powdery mildew, especially in humid conditions and where they are watered from above. Water at soil-level if you can and spray plants with diluted milk once a week in the morning – for a recipe see Powdery Mildew in the Pest-Control Quick-Guide on this blog.

Trimming off leaves that touch the ground and leaves that prevent good ventilation is an effective way to prevent diseases. Consider growing cucurbits up a trellis so they are off the ground and they take up less space.

I took this photo in an Italian backyard - Tromboncino squashes and a pumpkin

Train plants to have one leader by cutting off side branches as the emerge from the main stem. As a result the plant will focus on forming fruits instead of forming branches and leaves.

Cucurbits can suffer from blossom end rot. This is the name given to the ends of fruits going brown because they are rotting. In most cases blossom end rot is caused by inconsistent watering. The remedy for Blossom End Rot is a change of watering. Keep soil always moist but not sodden and blossom end rot may not re-occur in fruits that form thereafter. Where it persists, the cause will be a lack of calcium in the soil. Calcium can be added as lime or as gypsum.

Cucurbits such as cucumbers and zucchinis will be encouraged to produce a steady crop of tender tasty fruits by forever picking fruits before they reach full maturity. The reason is: once one fruit is allowed to reach full maturity (indicated by a yellowing of the fruit), the plant will decide that its job is done - it has produced viable seeds - and it will slow down or stop the production of new fruits.

Most cucurbits form male flowers and then further down the line - literally - they begin to form female flowers. Your plants may have a lot of flowers, but no fruits will form if there are no female flowers yet. Insects take pollen from male to female flowers. The absence of insects or the absence of female flowers may mean that there is no pollination and therefore no fruits. What to do about this is discussed in blog post Why don't my pumpkins have any pumpkins on this Food Garden Group blog. The methods described there apply to all cucurbits. I grow Lebanese cucumbers in my hothouse this season, had the door and window open on most days, and found that I did not have to do any hand-pollination. Monitor your cucurbits and hand-pollinate if required.

Crystal Apple cucumbers on a trellis in Karen D's garden last summer

After researching the subject, Food Garden Group member Karen D. decided to experiment. Putting into practice what is discussed above she built zucchini trees. The result was a steady supply of ripe juicy but not too large zucchinis that did not take up a lot of space in the garden. 

Karen builds zucchini trees as follows:

• In spring as soon as the change of frost is past plant one or two zucchini plants where-ever you have a little bit of space.

• Find a solid stake around 1.5 metres long and drive it into the ground on the shady side of the plant, so its shadow won’t put the plant’s growing tips in the shade. Make sure the stake is around 5 centimetres away from the plant and that it is driven in deep enough to not fall over under a bit of weight.

• As the plant grows, trim off side-shoots, so only the main growing stem goes skyward. Make sure that the leaf-stems closest to the stake are cut off close to the main stem.

• When the main stem is around 8 – 10 centimetres long start to tie it to the stake.

• Continue to trim off leaves, so always only the top four leaves remain. This is important as the plant will become too heavy if you leave more leaves and the stem may sag and distort. Cut the leaves into small bits and put on the compost heap or give them to your chooks.

• Pick your zucchinis when they are about 20 centimetres long as they will become too heavy for the stem if you leave them longer.

• Continue to tie the stem to the stake at 3 – 4 centimetres intervals.

• The plants begin to lose momentum in mid-season, so plant one or two new zucchinis in late December/early January, so you have fresh zucchinis from this second lot until the very end of the season.

Thanks Karen for this interesting contribution! I am sure we will see more zucchini trees in food gardens this summer.