Beth’s Guide for Growing the Cucurbit Family: Cucumbers, Summer & Winter Squashes, Pumpkins, Melons & Gourds

We get many questions from gardeners about members of the cucurbit family, so our expert Garden Advisor, Beth Benjamin, has summarized her advice for successfully growing these mainstay garden vegetables. I am very pleased to add Beth’s knowledgeable and experienced voice to our blog.

Seedlings growing under a berry basket

Gourd seedlings sown 3 weeks before last frost

Ornamental Gourds

Planting: When you plant is important: all members of the cucurbit family simply won’t grow happily in the garden until the nights are staying at least 50ºF (10°C). Wait until then to start seeds in the garden to get successful germination and good growth.

When planting cucurbit seeds directly outdoors, it’s wise to cover them with netting or plastic berry baskets to keep birds or other critters from eating the seeds before you even see them.
If your growing season is very short or you have problems starting seeds outdoors (or if you are just eager) you can start cucumbers and squashes in individual pots and transplant them when it’s warm enough. They are fast growing seedlings, though, and will suffer if they get too crowded, so don’t sow them any earlier than 3 weeks before you expect to transplant them outside. (Remember that if they are grown too long in the pots, they’ll be so slow to recover from the move that you won’t have saved any time.)

Note: Unless you have a very long growing season, gourds do need to be started ahead as the fruit takes a very long time to mature. Most climates get cold weather too soon to allow enough time if the gourd seeds are sown directly.

Be careful when you are transplanting cucurbit seedlings. Don’t leave them in the containers too long to become root bound and stunted. The soil should be moist (but not soggy) in both the pots the seedlings are coming out of AND the ground they are going into. That way the roots will loosen up and lower nicely into the hole. Take care not to damage the roots, and plant them at the end of the day when they can rest after transplanting in the cool of the evening.

Seedlings growing in a mound

Planting in Depressions or Mounds: Enrich the soil in a 3 foot diameter planting circle which can either be raised up or depressed, depending on your climate. If you are trying to conserve water in a hot dry place, then scoop the circle down a little to collect water.

If it is more important to have good drainage, make a flat raised mound (only a couple of inches high).
Plant 2 or 3 plants in each circle. If you are planting the seeds directly into the garden, plant 5 or 6 and thin them out, leaving only the 3 best seedlings to grow to maturity. Properly thinned plants will be healthy and won’t need to compete for nutrients and light, so you’ll get much better results.

Vining squash growing in a bed

You can also plant squashes and cucumbers in a bed or a staggered row, leaving room for the vines to spread across the bed and a path beside it. Sow 2 or 3 seeds about 1½ feet apart, thinning to the best seedling in each group. All the cucurbits need rich soil and enough water - mulching is a good strategy to hold in soil moisture and keep down weeds at the same time.

Trellising: In a small space garden it’s a good idea to grow cucumbers up a trellis or fence. Growing the vines up also protects fruits from damage or disease from lying on moist ground. Gravity helps long cucumbers grow straighter as they are hanging down.

Gourds growing on a fence

Melons and mini-pumpkins can be trellised also, but the fruits need to be supported to keep them from tearing the vines as they get heavy. Gourd vines are very amenable to growing up wire fencing, as they are sturdy plants with strong tendrils that twine well. Vining winter squash and larger pumpkins do best left to trail on the ground with plenty of space for the vigorous vines.

Gourds growing on a metal arbor

Pollination: I get a lot of questions from gardeners concerned that they are getting flowers but no fruit.

Male & female squash flowers

Cucurbits have both male and female flowers. The female flower has a small embryonic fruit between the stem and the blossom that will fall off if it isn’t pollinated. The male has no little fruit; the flower joins the stem; and it has the pollen. Both must be blooming at the same time for the insects (bees or other little winged pollinators) to carry the pollen from the male to the female. Very often one type will bloom before the other, so if it is early in the plant’s life, I usually advise patience.

Hand-pollinating squash blossoms

If there are no flying insects to do the pollination, you can hand-pollinate in the early morning after the dew has dried but before it gets too hot, either by picking off the male flower and kissing the female flower with it, or by using a small watercolor type paintbrush and dabbing pollen from male to female flower.
 
Harvesting: It is important to harvest cucumbers, especially lemon and Armenian, before they get too big and mature. Lemon cucumbers should be a very pale yellow – when they get fully yellow colored, they are overripe and usually seedy with tough skins. If your cucumbers are bitter, it is probably because they didn’t get enough consistent watering. They need to be watered regularly; if you put your finger in the soil and it is dry beyond the first joint, the plants need water. If the fruits are misshapen, they probably didn’t get fertilized well, or are stressed from not enough water.

Summer squash like zucchini and patty pan can be picked when quite young, even before the flowers fall off, but I think the taste is best and yield is better when zucchinis are no more than 5 or 6 inches, and scallops about 3 inches. While you can pick them a little bigger, it’s important not to let them get so big that seeds develop and rinds are tough because both taste and texture will really suffer. If you check every day or two, you will rarely be trying to give away baseball bat size zucchinis. Now and again you miss picking one and you’ll have a giant to stuff or make into zucchini bread.

Hard-shelled winter squash is ready to pick when the stems are hard and the rind can’t be pierced with a thumbnail. They continue to get sweeter if they are left on the vine as long as possible, though. Before heavy frost, cut the stems about an inch above the fruit, and let them mature in the sun for 7-10 days to harden and toughen the skin. Then store in a cool dry place with good air circulation.

Do Make A Second Planting: Except in the very short season areas, it is really worth making a second planting of summer squash and cucumbers, both for salad and for pickles, in early to late June. These heat lovers grow so quickly with seed sown directly into warm summer soil and begin to ripen fruits around just six weeks! Why waste your precious garden space on old, declining squash plants, when you can plant new ones and have continuing delicious harvests to enjoy throughout the season.