Starting Seeds in the Greenhouse: Cucurbitaceae Family

By high summer, you may find gardeners with a serious problem of overabundance begging you to take their cucumbers, squash and melons—that’s because these ambitious growers underestimated the bounty that cucurbits bring to the garden. Although they’re cursing their fertile vines now, there’s a good chance they’ll plant the same ones again next year because they miss the sweet flavor of melon or versatile flesh of summer squash. Gardeners are fickle beasts, but cucurbits are extremely reliable.

Growing them in your greenhouse may be a serious challenge, but you can always use it to get a jump on the growing season. In areas where the summer is short, these heat-loving vines can be encouraged to produce sooner when they’re started inside in biodegradable pots. If you want to try your hand at cucurbits in the greenhouse, look for bush varieties to help contain the chaos that the sometimes extremely long vines can create.

A basic and flexible vine

Tomatoes and peppers get most of the glory every year, but your garden wouldn’t be the same without the cucurbits. These often easy to grow vines are more than just food sources, their big, bold flowers attract pollinators from far and wide, so not only are they producing food for your table, they ensure that the other vegetables nearby bear abundantly as well. And that’s as it should be—cucurbits have always been supporting players.

They’ll do best if you provide them with lots of support in the form of trellises or A-frames to climb. Bigger fruits like muskmelon can be tied up with nylon stockings or flexible tubing, but giant pumpkins and watermelons are best grown on hills and trimmed to keep them tidy—there just isn’t a trellis big enough to support a supply of 40-pound fruits.

If you’re considering growing any of these flexible fruits in your garden, start them six to eight weeks before the main growing season and wait to transplant them until the soil is warm. You don’t want to start vining types too soon because their explosive growth can take over a greenhouse in no time.

Asian cucumbers – Asian cucumbers are actually a type of melon, but I broke them out in case you wanted to grow some. These mild-flavored fruits are lovely in salads and do best when trellised. Otherwise, the long, skinny fruits may curl or become seriously misshapen.

Your Asian cucumbers are heat-lovers, so wait to start them until you can keep the temperatures in the greenhouse well above 50 degrees Fahrenheit (10 degrees Celsius). Start seeds indoors in compressed peat pots at temperatures between 60 and 95 degrees Fahrenheit (15 to 35 degrees Celsius). Push seeds about 1/2 inch below the surface of the soil and watch them closely, germination usually takes place in just three to five days.

Cucumbers – Cucumbers appear in both pickling and slicing varieties, and though either can be pickled or sliced, picklers usually have shorter fruits with thinner skin and bear just a little earlier. Both will do better if they’re trellised, or select bush varieties if you have limited space for cucumbers. A couple of bushing plants will produce more than enough cucumbers for the whole family.

Cucumbers are among the easiest plants in the garden and their big seeds are easy for kids to handle, so they make a great choice for introducing youngsters to seed starting. Seeds won’t germinate at temperatures below 50 degrees Fahrenheit (10 degrees Celsius), so make sure to warm your soil completely before you plant your seedlings in individual peat pots. Once the soil is between 65 and 90 degrees Fahrenheit (18 to 32 degrees Celsius), push the seeds 1 to 1 1/2 inches into the soil. Germination should happen quickly, but any time between three and 10 days is normal.

Edible gourds – Gourds may be better known for their service as bird houses or exfoliating sponges, but there are edible varieties as well. In fact, most are edible when they’re young, though some types may be very bitter. Gourds sold as edibles are similar to squash in taste and texture and some can be used for crafts if left to fully mature on the vine.

Gourds grow very much like winter squash—they love the heat. Warm the soil to 70 degrees Fahrenheit (21 degrees Celsius) before you plant your seeds about one inch deep, then hold them between 70 and 105 degrees Fahrenheit (21 and 40 degrees Celsius). They’ll emerge in five to 10 days, then grow like mad.

Melons – For many growers, melons are the essence of summer, and with so many to choose between, it’s easy to understand why. The familiar muskmelon and honeydew can be grown in your garden, but don’t stop ther—check out the many other varieties this family has to offer, such as the Crenshaw melon or the vine peach.

Plant your melon seeds 1/4 inch deep in individual pots with the soil warmed to at least 60 degrees Fahrenheit (15 degrees Celsius) and they’ll emerge in three to 10 days. It can be tempting to plant several different types of melons, and there’s no reason not to—but if you do, make sure to label each variety carefully. Otherwise, it’ll be impossible to tell them apart until they fruit. Wait to move your melons to the garden until the soil is warm.

Summer squash – Appearing in a wild assortment of sizes, shapes and colors, summer squash are among the most planted cucurbits in the garden. Bushing types make excellent edible landscaping or container plants, provided they have at least five gallons of soil to root into. Imagine the look on the face of visitors when they notice zucchini or colorful scallop squash growing among the giant ornamental leaves gracing your walkway.

Summer squash seed won’t germinate if the soil is too cold, so make sure to warm your peat pots to about 70 degrees Fahrenheit (21 degrees Celsius) before you start planting. Push seeds about one inch into the soil and water them well; they’ll emerge in five to 10 days.

Watermelon – The uncontested Kings of summer, you can grow watermelons that sport pink, orange or yellow flesh, and even those fancy seedless watermelons if you have the space. They can be slow to set fruit, but once they start, watch out because summer’s just around the corner. It’s very important to raise fruits above the ground with mounds of mulch to keep them from getting overly wet when you water—otherwise your fruit may rot before you get to dig in. Watermelons like it hot, so warm the soil to between 60 and 95 degrees Fahrenheit (15 to 35 degrees Celsius) before you start your seeds in individual peat pots. Plant them about 1/2 inch under the surface of the soil and in three to 10 days your seedlings will start to appear. Even moisture throughout their lives is vital to success with watermelon seedlings so make sure you water carefully.

Winter squash – Contrary to what their name should imply, winter squash need long, warm summers to succeed. They won’t do well if planted too soon—frost is a big killer for this group that includes pumpkins, acorn squash and spaghetti squash. Pay close attention to the days to maturity listed on the seed packet and choose those that can complete their lifecycle well within your growing season for best results.

Like other cucurbits, it’s best to plant winter squash seeds in individual peat pots with the soil already warmed—the magic number is 70 degrees Fahrenheit (21 degrees Celsius) for these squash. Plant winter squash seeds about an inch deep and you’ll have sprouts in five to 10 days.

[ background=”#0e2d08″ color=”#a68914″]Kristi Waterworth[/]

image: jean-louis zimmermann via Compfight cc

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