Transplanting Melon & Cucurbit Seedlings into Dirt

By Rich Hamilton
Published: March 13, 2023 | Last updated: March 13, 2023 11:06:18
Key Takeaways

Transplanting cucurbit seedlings, like melons, can be tricky as the roots are very sensitive. Follow Rich Hamilton’s tips and you’ll have no trouble growing big, juicy melons, cucumbers, and squash outdoors.

Many of the most popular vegetables to grow at home belong to the cucumber family and are known as cucurbits. These vegetables grow on vines that can either run along the ground or climb vertically. Cucurbits include squash, zucchini, winter squash, pumpkin, watermelon, cantaloupe, cushaw, luffa, and cucumber.


Pumpkin and watermelon vines require growing room but can train over structures. Cucumbers and rock melons need less space and can be grown vertically on a trellis or obelisk. Do it right, and you will enjoy a pile of tasty fruit and veg that will last a while.

As a rule, cucurbits do not like to be transplanted. This is because they have sensitive roots that do not like being disturbed. It is possible to successfully transplant cucurbits, however, if you do it with care. Here we will look at what you need to know to transplant your cucurbits from indoors to outdoors successfully.


For this example, we shall use melons because they dislike being transplanted and are also very temperature sensitive. So, if you can learn to transplant melons, you should have no problems with any other cucurbit.

Melons are incredibly versatile. They make a healthy dessert or snack and can be used as an ingredient in many recipes. Melons come in a variety of colors, sizes, and flavors. Pick one you know you will enjoy eating. Think about the size of your growing area. Melons are vining plants and, as such, need a lot of space.

Starting Melon Seeds

grower planting melon seeds


Sow seeds at a depth of four times the size of the seeds when all risk of frost has gone. Bury two seeds in 3.5-inch pots and keep them on a warm sunny windowsill or heated propagation mat. The sweet germination spot is 68°F. Water seeds in well, but don’t water them again until they germinate — they are prone to rotting.

Disregard the smaller of the two seedlings once their first true leaves are through. Grow your remaining seedlings at around 59°F until they have produced at least three more true leaves. Once they have reached this stage, re-pot them into one-gallon pots and harden them off.


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Hardening Off Melons & Cucurbits

You must harden off your young melon plants for at least a week before planting them. “Hardening off” means getting your plants used to an outdoor environment. Set them outside in a shaded position for an hour or two. The next day, give them a more extended visit outside until they remain outdoors overnight, still in their pots. Remember that they are susceptible to freezing temperatures. If you should experience an unexpected cold snap, bring them inside until temperatures rise again.

Once they are hardened off, the seedlings are ready to be transplanted. Dig your holes and fill each one with compost or equivalent. Be very gentle and quick when physically transplanting your seedlings. The roots do not like to be disturbed once they are in; mulch around them with grass cuttings for a nitrogen boost.

Watermelons need a long growing season with relatively high temperatures: between 70-80°F during the day and between 65-70°F at night. Space them about two feet in rows 6-8 feet apart. Plant in full sun, in a rich, sandy, well-drained soil. Remember to be very gentle with the roots as they hate being disturbed. Water regularly while growing. Once you hit ripening, however, keep the soil slightly drier if you want the best flavor.

Once transplanted, if you should encounter a freak cold weather snap, do not worry; not all is lost. Try making a mini-propagation cloche out of a one-gallon plastic milk bottle. Cut the bottom off and place it over the plant, pushing it into the soil slightly to keep it steady. Vent your plant during the day by removing the bottle lid.

Top Tips for Growing Melons

grower transplanting melons into soil

You can try planting your melons through black plastic mulch if you live in colder climates. This works because it absorbs heat, warms the soil early, helps retain moisture, makes harvesting easier and cleaner, and keeps weeds, pests, and diseases away.

Melons require a lot of sustenance to grow as big as they do. You will need to provide plenty of nutrients and water. They should have a minimum of one to two inches of water a week — in the morning, preferably via a drip irrigation system. Add roughly two inches of compost to all root areas monthly for an extra boost.

Melons thrive in humid or semi-arid conditions. However, they will be less prone to fungus or disease in drier climates. They also prefer sandy loam soil where possible.

All cucurbits prefer total sun exposure. Their leaves orient themselves to the sun. Moving the vine and disturbing the orientation can set the plant’s development and fruiting back. At the same time, the energy goes into slowly re-orienting the leaves to the sun.

Planting Out Other Cucurbits

melon and tomato plants growing near a window

When growing summer squash, courgettes, and cucumbers, you can use the same method for planting out as we used above for the melons.

Winter squash is best planted 6.5 feet apart; courgettes can go closer (about three feet apart). As they climb, cucumbers can go about 1.5 feet apart. It is always tempting to try and squish a few more in but be warned that it will be at the cost of your yield.

The foliage of cucurbits like zucchini and squash is easily damaged and dried out, so grow in a protected position. Keep soil evenly moist as irregular watering can lead to low-quality fruit.

Cucurbits are prone to fungal disease and need good airflow around the vines. Generally, allow for 6.5 feet between melon and pumpkin vines, more than three feet between squash and zucchinis and almost a foot between cucumbers.

Cucurbits are strong growers. Apply organic fertilizer in the first week after planting. Repeat regular light applications every three to four weeks. Avoid watering the foliage and fruit to keep fungal problems to a minimum.

Growing cucurbits is very rewarding. Picking varieties based on what you like and will eat will make it more worthwhile. With cucurbits there are many choices, from sweet melons to savory squashes. Now that you have a few more tips to help you get them growing big and healthy, you have no excuse not to give them a try.


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Written by Rich Hamilton | Writer, Consultant, Author of The Growers Guide

Profile Picture of Rich Hamilton

Rich Hamilton has been in the hydroponics industry for more than 20 years, working originally as a general manager in a hydroponics retail outlet before becoming an account manager at Century Growsystems. He enjoys working on a daily basis with shop owners, manufacturers, distributors, and end users to develop premium products.

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