Okay, so this family of vegetables does have a pretty intimidatingly geeky name, but I hope that didn't scare you off, as they are a lovely group of plants. The 'Cucurbits' (Short for cucurbitaceae...Cue-kurr-bit-ace-ee-aye...) include pumpkins, zucchini, squash, cucumbers, melons and variations in between. The fact that they sometimes have tendrils is but one of the things that makes them nifty.
Zucchinis must be one of the most productive crops that can be grown over summer, especially in terms of dollar value of vegetables harvested. Just two or three zucchini plants can keep a household bountifully supplied for the mid to late summer. While pumpkins provide a rambling vine plant to take over the nether regions of your garden and produce a delicious crop. In Otago, cucumbers are best grown in a glasshouse, where they can provide good yields of cucumbers for salads and sandwiches, or grow the smaller pickling varieties and make your own fermented or pickled gherkins!
Zucchini and other Summer Squash
When to plant: Sow direct after the last frost (so some time in November) or sow indoors mid October and transplant after last frost.
Spacing: Plant at least 60cm and up to 1m apart.
Soil requirements: Heavy feeders, so love compost. You can sow or plant them in a mound of compost.
Watering: Don't like to dry out so water regularly and mulch around your plants.
Harvest and Use: When plants start fruiting heavily it is important to harvest regularly. I pick Zucchini when they get to about 15cm max. You can also pick them when they are smaller and use the flowers too. Be vigilant, as letting a fruit turn into a marrow can permanently deplete the plants future ability to produce fruits.
Seed Saving: Zucchini plants are pollinated by insects. They will cross pollinate with other varieties of zucchini or squash. So for seed saving, its best to be growing only one variety of zucchini in your garden.
To save seed from zucchini, it is ideal to grow several plants, so that you can choose the best one or two to save seed from. This is because for seed production you need to let the zucchini grow to 'marrow' size. This generally slows or stops the production of more fruits on that plant. So more plants will continue to give you crops of zucchini as well as enabling you to select the best plants for seed.
A zucchini fruit is 'ripe' for the picking when its skin has gone hard and a bit dull, and usually it will have an almost hollow sound to it when you knock on the fruit. When the fruit has reached this stage, pick it and put it somewhere to 'cure' for a while. A place such as a pantry works well. This gives the seeds a chance to finish off maturing just incase they weren't quite ready yet.
After a month or so of curing the marrow can be split open, the seeds scooped out, and rinsed in a kitchen sieve to wash off any excess flesh. The seeds can then be spread out on a plate and dried for a few days in a warm spot out of direct sunlight. Fully dried seeds can then be stored in an airtight container such as a glass jar or zip lock bag.
When to plant: Sow direct after last frost or start in trays / pots indoors in October and transplant outside once plants have a couple of proper leaves. Pumpkins tend to do best if they are direct sown as they form a 'tap root' very quickly after germination and if this is broken at all (very easy to do if transplanting), it will be greatly weakened and form multiple smaller roots rather than a very deep and efficient tap root.
Pumpkins prefer a very sunny spot. They are a good crop for making use of 'wild' parts of the garden as they will happily trail over most weeds and grasses, provided that their roots are in good soil.
Spacing: About 1 meter apart. And keep in mind that pumpkins will creep around the place with their vines getting up to 3 meters long or more.
Soil requirements: Pumpkins love rich, well manured soil. A mulch layer of straw also helps hold moisture in.
Watering: Pumpkins do enjoy an abundant supply of water but also make sure that they have good drainage. Water twice a week if its not been raining, or less if a mulch layer is used. It's easy to tell when pumpkins need water as their leaves go droopy.
Harvest and Use: Harvest pumpkins in autumn as soon as the first frost kills off the leaves of the plants. Always leave a few cm of stem on the pumpkin unless you're going to use it straight away as this increases their storage life considerably. Keep them in a cool, dry, dark place for long term storage. Pumpkins are used in a wide variety of dishes including roast veggies, soups, curries, pies, etc.
Seed Saving: Pumpkins are pollinated by bees and they will cross pollinate with other varieties of pumpkin. As such it is best to only grow one variety of pumpkin in your garden if you are intending to save seeds.
Saving pumpkin seeds is simple. Take note of which pumpkins came from well performing plants. This can be done by marking their skin with a permanent marker, or tying a ribbon around their stem.
Then, when you go to eat the pumpkins, scoop out the seeds. Save seeds from the best pumpkins that have thick flesh and general good characteristics. Rinse the seeds in a kitchen sieve to wash of excess flesh. Then spread them on a plate to dry out in a warm place out of direct sunlight for a few days. Store dried seeds in an airtight container in a cool dry dark place.