Q&A for How to Grow Watermelons

Yes, laying down plastic before you plant will help with soil moisture retention and weed control.

Before you add fertilizer, it helps to know the current condition of your soil. Conduct a soil test or take a sample to your local extension office to find out what your nutrient levels are. Based on that, you may need to add nitrogen, phosphorus, or potassium in varying amounts.

Plant your watermelon in the spring after the threat of any frost or cold weather has past. In terms of timing and temperature, they are a lot like tomatoes and love warm weather.

It's best to just let them grow, as not all of the flowers and baby melons will fully grow. It is very likely that some of the baby melons will rot or get eaten by bugs before you can pick them.

In my experience size is not an indicator of ripeness. I know some sugar baby watermelons get as big as basketballs but I have grown some that were ripe and only softball sized.

A watermelon is ready to harvest when you knock on it and it makes a hollow sound, almost like the sound you make when you knock on a door or wall. Also, if you look at the bottom of your watermelon, where it sits on the ground, there should be a white or pale yellow spot. This spot will be pale yellow if your watermelon is ripe.

Watermelons like loamy, well-drained soil. Amend soil with aged manure, seaweed, and/or compost before planting. Watermelons prefer a soil pH rating between 6 and 6.8.

Watermelons, depending on what type you have, normally take about four months to completely ripen, though some ripen a little early, and some a little late.

Plant each watermelon vine two feet apart in hills five feet apart. So if a watermelon plant needs five square feet of space (5x2/2), and an acre is 43,560 square feet, 43560/5 = 8,712 plants. You will need more seeds than this, as some will not germinate or are too weak.

Depending on the type of watermelon you've planted, it's normally two to five watermelons per vine, so the number of watermelons you get depends on how many vines you have on your plant or plants. It also can vary depending on how well you've taken care of your watermelon plants.

If the black spot is on the end where the flower first formed, then your plant suffers from what is known as blossom end rot which, in most cases, is caused by a lack of calcium in the soil. To add calcium to your soil, add powdered eggshell or calcium carbonate the year before planting. If the need is immediate, find a liquid variety of calcium that can be mixed with water and added as either spray or as a root drench.

Yes, you can. In many cases it would not grow well, because some seeds are not mature enough to bear fruits.

Cow manure is recommended; however, other chemical fertilizers can be used depending on the lab test of your soil.

Yes, watermelon with seeds is still commonly grown.

This can be a sign of nitrogen deficiency, so consider getting some nitrogen-rich fertilizer. You could also be giving your watermelons too much water.

Not all of the flowers on every watermelon plant will produce a melon. It could be your watermelon isn't getting enough sun or water, or maybe the soil isn't the best for planting watermelons. Regardless of whether your watermelon plant has the right nutrients and soil/sun/water, the flowers will not produce watermelons if they aren't pollinated, and there's nothing you can do about that.

Most watermelon seeds will have some kind of color when they are mature, whether that's red, black, or mottled brown. (A few are white.) Generally, if the watermelon you're eating from is ripe, the majority of the seeds will be mature enough to plant. Eliminate any seeds that are thin or much smaller than the majority.

A clean piece of wood or a large, flat stone should work. Just make sure whatever you use is big enough for the watermelons to fit on.

It normally takes about four months for a watermelon to grow, although some grow a little faster or a little slower than others.

If the flesh is hard, it could be a citron watermelon. They're hard to cut because of their thick rinds. It cannot be eaten raw, but it can be used for pickling and baking. If the flesh is tender, it could either be a Cream of Saskatchewan or White Sugar Lump variety of watermelon, which grows to about 10 pounds. It could also be a red, tender watermelon that has cross-pollinated with a citron melon.

Apply NPK 20:10:10 two weeks after planting, and Urea at the onset of flowering.

Yes, but you have to be very careful not to damage the roots of your watermelon.

Any pesticide use must be specific to an insect or disease problem. Carefully inspect the plants every day or two. If you encounter an issue, enlist the help of a professional to tailor any treatment to the infection or infestation. Pesticides are pathogen specific as well as crop specific.

Cow manure is good for all types of plants and trees.

Each seed may or may not grow completely, but each plant can grow 2-5 watermelons on average. This may vary due to the kind of watermelon and the length of the vine.

Yes you can, unless it is a hybrid. If it is a hybrid it will grow a vine but no fruit.

Sow 8 to 10 watermelon seeds in a hill, and push seeds 1 inch into the soil. Space hills 3 to 4 feet apart, with at least 8 feet between rows. Thin plants to the 3 best in each hill. Keep soil free of weeds by shallow hoeing or with a layer of mulch.

Some time in summer, usually. It needs to be hot, but not too hot. Just make sure you water them enough and you'll be fine.

A soil amendment (usually called soil conditioner) is a product which is added to soil to improve the soil’s physical qualities, usually its fertility.

I wouldn't recommend this as Visqueen is a vapor barrier. It might starve the watermelons of oxygen and trap too much moisture inside, causing them to rot.