How to grow summer squash

This is the complaint people actually bring to this crop, and it is almost never a disease. A squash plant carries separate male and female flowers. The female is the one with a miniature fruit already formed behind the petals; the male sits on a plain stem. Pollen has to be physically carried from a male flower to a female one, by an insect, on the single morning the female is open.

If that does not happen, the little fruit yellows, shrivels at the tip and drops. It looks like rot and it is simply a flower that was not pollinated.

Two ordinary situations produce it. Early in the season a plant often opens a run of male flowers before any females — that is normal and needs no action. And in cool, wet or windy weather bees do not fly, so females open and close unvisited. In the maritime Northwest the second is much the commoner cause.

You can do it yourself in about fifteen seconds. Pick a male flower, tear the petals off, and dab the pollen-covered anther directly onto the centre of an open female. Do it in the morning while the flower is open. It is also exactly how you would isolate a variety for seed saving, which is the one realistic route to saving squash seed at garden scale.

Squash is tender and fast. There is nothing to gain by sowing early — a plant set out into cold ground sits and sulks while one sown two weeks later overtakes it. Our calendar puts direct sowing a week after the last frost and transplants two weeks after, which is deliberate.

If you start plants early, start them in something you can plant whole. Squash roots hate disturbance, and a plant knocked out of a plug and teased apart takes a fortnight to recover.

Feed the ground heavily. This is a plant that builds an enormous amount of tissue in a short time, and the traditional method — a spadeful of compost or rotted manure buried where each plant will go — is still the simplest way to do it.

Then plant fewer than you want to. Two plants will feed a household through a summer and three will overwhelm it. This is not a joke about gluts: the plants get large, and a crowded squash bed is a mildew bed.

Solomon's unwatered spacing makes the scale plain — a sprawling heirloom summer squash can dry out a circle eight or nine feet across, and he insists on thinning each hill to a single plant because there must be no competition for water.

A squash plant stops setting new fruit once one is left to mature — the same logic as beans and peas, and more abrupt here because a single marrow is a large investment for the plant. One overlooked zucchini under a leaf will shut down production for a week.

So pick small and pick constantly. A zucchini at six to eight inches is better eating than one at fourteen, and picking at that size keeps flowers coming. In hot weather that means checking daily; fruit can go from perfect to marrow in about forty-eight hours.

Look under the leaves properly. The fruit hides, the leaves are large, and the ones you miss are exactly the ones that stop the plant.

Cut rather than twist, leaving a short stem. Twisting tears the plant and opens a wound at the crown where rot starts.

The flowers are also a crop, and a better one than most people realise. Male flowers can be picked freely once a few are open — the plant produces far more than it needs — and they are excellent stuffed or fried.

Powdery mildew is inevitable rather than preventable on this crop. White dusty patches appear on the older leaves in late summer and spread. Good spacing and airflow delay it, watering at the base rather than overhead helps, and removing the worst leaves keeps the plant going — but every squash plant gets it eventually, and by the time it does you have usually had all the squash you wanted.

Squash vine borer, where it occurs, is more serious: the larva tunnels inside the stem and the whole plant wilts suddenly with no warning. It is largely an eastern and midwestern problem in North America and much less of an issue in the Pacific Northwest.

Cucumber beetles chew flowers and seedlings and can transmit bacterial wilt. Row cover over young plants protects them — but it must come off once flowering starts, or you have solved the beetle problem by creating a pollination one.

Blossom-end rot on the fruit, and rot generally where a fruit sits on wet soil, are both about water and contact. Mulch under developing fruit and water evenly.

One thing that is not a problem: enormous leaves wilting dramatically at midday and recovering by evening. A squash plant transpires faster than its roots can supply in full sun, and afternoon wilt on a plant that recovers overnight needs no action at all.