Vegetable harvesting: It's all in the timing

Vegetables are annual plants that grow from seed, mature, flower and set seed all in one season. Photo / Thinkstock

Giant zucchini are the trophy of the nouveau vegetable gardener. These big green squash that reach the diameter of a human leg are awesome to behold, but crack one open and it's all pith and seed. It's useless for everything except hollowing out into a big green casserole. Giant zucchini are also bad for long-term production. Here's why.

Vegetables are annual plants that grow from seed, mature, flower and set seed all in one season. They're fast and furious producers because each squash or tomato or eggplant contains seed.

In the wild, these fruits serve one purpose. They rot after the plant dies to fertilise the ground for the seed to sprout the next year. Some are even designed to have fruits eaten by animals, forcing seed through their digestive tract to emerge with a fertile pile of dung. Either way, it's all about seed survival.

When your squash flowers mature, they form tender fruits containing seeds so tiny you barely notice them. If not picked promptly, the zucchini fruit continues along its predestined course of reproduction, the seed inside growing larger.

When the seed matures in a fruit or pod, it signals to the plant that its job is done. Slow down - next year's progeny is taken care of.

Every plant that forms a giant zucchini receives just such a message. It slows bud formation or halts production entirely. This is the impact of just a single zucchini allowed to mature. It kills the late-season potential for that plant. But if you are prompt with all your summer squash harvesting, you can drive them to produce far longer.

This concept applies to many other plants in the food garden. Unless you are growing shelling peas, seed production is your enemy. Pick fruit young and pick often to load up the kitchen with tender, flavourful produce every day.

Picking promptly is even more vital with other vegetables such as edible pod peas and beans. These are vegetables originally developed for the seeds they contain. Over time, breeding developed new strains with pods so tender, these too are edible.

But in every snow pea pod and French string bean are fibres that evolved to hold the developing seed for a long time. In nature the pod would mature, dry out and then scatter the seed, sometimes months later.

Any edible pod pea or bean left to mature even a day too long becomes fibrous and loses a good deal of its flavour. Thus, picking these vegetables twice a day during peak production may be the best way to ensure yours come into the kitchen fresh and tender.

For those who love sweet bell peppers, picking too early can be a disadvantage. This fruit takes time to build up sugars in its flesh. Many green bells will turn red or yellow when very ripe, as do savoury pimento peppers, one of the thickest-walled forms.

When you pick peppers and eggplant, bring along your clippers to cut the stem cleanly. When very ripe, the pepper flesh softens a bit, so the stem may pull out of the fruit with very little effort. The same applies to both tomatoes and eggplant. Once the stem base is gone, the fruit won't keep longer than a day because it quickly dehydrates through the exposed flesh.

Each kind of vegetable you grow should be viewed as an individual. Each one should be picked on a different time schedule to obtain the most tender, sweet or flavourful fruit.

When it comes to how long they produce, just remember that giant zucchini. It may look great, but size does matter, and not always in the ways you might expect.

- AAP