MUSKMELONS / CANTALOUPES / SPANSPEKS / ROCK MELONS

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  • If this article on growing cantaloupes was written in Australia, we’d call them “rock melons.” In South Africa, we’d be writing about “spanspeks.” Here in the U.S. we call them either muskmelons or cantaloupes.
  • You’ll do better growing cantaloupes in a warmer climate, but you can successfully grow some varieties in cooler climates like where we live in NE Washington.
  • If you want to make some good money growing muskmelons, grow and sell them in Japan. As of September 2010 they were selling for over $30USD at food markets in Japan.
  • Muskmelons are members of the cucurbit family, as are squash, cucumber, and watermelon. They all share similar growth patterns and nutritional requirements to muskmelons, especially watermelon.

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WHEN TO PLANT MUSKMELONS/CANTALOUPES

  • Muskmelons or cantaloupes? These terms will be interchangeably used throughout this article.
  • Short-season cantaloupes ripen in approximately 65 to 75 days, whereas the average cantaloupe ripens in about 85 days.
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  • Whether you’re planting seeds directly to your garden or transplanting your melon plants, never plant in soil temps below 60°F.
  • In Northern climates, you’ll want to start your plants about 4 weeks ahead of your target transplant date.
  • In Southern climates, you can direct seed once danger of frost is past and your soil temps are at least 60°F.
  • If you live in a cooler climate, you may have no choice but to start the seeds ahead of time in soil blocks or small pots.

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WHERE TO PLANT CANTALOUPES/MUSKMELONS

  • Protecting melon plants from cold temperatures will produce better results. The more warmth your vines get, the more fruit your plants will produce at harvest time.
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  • Muskmelons require full sun and plenty of heat. Give them the sunniest spot in your garden with good air circulation. You want your melon plants to dry out quickly after a rain to prevent diseases.
  • Cantaloupes like it hot and thrive best at temps of 70° to 95°F.
  • They like well-draining soil that has a good amount of humus (rotted matter like manure, compost, leaves, etc.)

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PREPARING THE SOIL

  • Cantaloupe and Muskmelons require a pH level no lower than 6.0 up to about 7.5.
  • These melons need a good amount of calcium in the soil to prevent blossom-end rot.
  • Melons prefer soils with a pH between 6.0 and 6.8, which indicates adequate calcium availability—an important guard against blossom-end rot.
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  • While melons need the big three nutrients, nitrogen, phosphorus, and potassium (potash), or N-P-K, they have less need for nitrogen than many fruits and vegetables and a greater need for potassium.
  • If you have not-as-good draining soil, you can improve your drainage by creating 6 to 8 inch raised beds.
  • Rototill or spade 2 to 4 inches of finished compost and/or well-composted manure 6 to 8 inches deep into your rows before planting your melons.
  • If you don’t have enough compost to cover your rows deeply with, use concentrated amounts where your plants will be located.
  • This pre-composting of your soil provides the needed nutrients for your melons, distributes moisture evenly, and helps their roots get sufficient oxygen.

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CHOOSING THE RIGHT SEED VARIETIES FOR YOUR AREA

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  • It’s a good practice, before ordering seeds, to find out from your county extension what seed varieties are resistant to fusarium wilt or other diseases common to cantaloupes/muskmelons in your region.

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GERMINATING MUSKMELON/CANTALOUPE SEEDS

  • Melon seeds are typically usable for up to 4 years after you’ve purchased them initially, provided you’ve stored them in a cool, dry, and dark location.
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  • You’ll need your soil temperature to be a minimum of 60° to 100°F, although the accepted optimal temperature would be at 85° to 90°F.
  • Seedling should emerge at around 3 to 5 days if the soil is at 90°F, and at about 10 to 12 days if your soil temp is 70°F.
  • Don’t allow your soil temps to drop below 60°F or your seeds will simply rot.

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PLANTING MUSKMELONS/CANTALOUPES INDOORS

  • It is recommended for planting seeds indoors to use a sterile potting soil so as to allow your seedlings the best chance at germination and survival.
  • Plant your seeds in tapered plastic pots, soil blocks, or plastic trays for easy transplanting.
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  • While some gardeners recommend using peat pots, we aren’t crazy about them…they don’t decompose as quickly as we like, so we’re recommending soil blocks for those who prefer to not use plastic containers.
  • Cantaloupe seeds need light to germinate, so plant your seeds ¼” to ½” deep so that they’ll get some light.
  • We plant 2 or 3 seeds per pot, and if all three come up, we select the biggest one after the plants have at least 2 true leaves – around 2 inches tall – and snip the others off at soil level.

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TRANSPLANTING YOUR SEEDLINGS TO YOUR GARDEN

  • As with most fruits and veggies, we strongly recommend that you “harden off” your muskmelon seedlings before you transplant them to your garden.
  • This entails moving them out of doors during the daylight hours – into the evenings later in the process – for 7 to 10 days, as well as reducing their water gradually.
  • Don’t fertilize the seedlings during the hardening off process; make sure they’re protected if the weather becomes windy and/or rainy.
  • Your seedlings should be around 3 to 4 weeks old when you transplant them. They’ll have at least two true leaves and be at least 2 inches tall.
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  • Minimum air temps should be around 70° to 75°F during the daytime and 60° to 65°F in the night time.
  • If you live in a Northern climate, we strongly advise using a black plastic “mulch” to warm up the soil before planting.
  • When you transplant your muskmelons, make sure you handle them carefully; don’t disturb the roots.
  • Transplant muskmelons to your garden early in the day, or in the evening to avoid stressing them.
  • If you’re planting to rows, space your plants 2 to 4 feet apart, and make the rows 4 to 6 feet apart. If you’re planting hills, 4 ft apart should be fine, but check your seed packets for recommendations as some varieties sprawl more than others.
  • Set your plants just a little deeper than they were in the pots so that there’s a bit of an indentation at the base of your seedlings.
  • Water your seedlings thoroughly – but don’t drown them!
  • Use row covers to protect them for the first few days from sun and pests. You can leave them on until the plants flower.

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PLANTING SEEDS DIRECTLY IN YOUR GARDEN

  • In Southern climates, you have the advantage of skipping the previous sections and planting your seeds into the garden.
  • Make sure your soil is a minimum of 60°F. If you need to aid the soil temperatures in getting to that level, it’s a good practice to use black plastic to bring your temps up.
  • If planting in rows, we typically space our plants about 2 feet apart and our rows 4 feet apart. It is a good idea, though, to plant seeds every 4 to 6 inches and thin your plants once they’re a couple inches tall.
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  • If you’re planting hills, space them at least 4 feet apart, on center, and plant 5 or 6 seeds on each hill, later thinning them to 2 or 3 of the best seedlings.
  • Outdoors you can plant your seeds from ½ to ¾ inch in the soil as the sun will penetrate deeper than grow lights if you plant your seeds indoors.
  • Lightly pack your soil around the muskmelon seeds; don’t pack the soil so tight it forms a crust.
  • Row covers may be beneficial early in the season to keep your plants warmer and keep bugs out. Make sure you remove them by the time your plants flower, though, or the bees won’t be able to pollinate your muskmelons.
  • If your soil doesn’t drain well, it’s a good idea to mound your soil either in hills or rows. In our area, because our soil is so rocky, we don’t need to raise our beds.
  • Make sure you know the variety of seed your using as some plants will sprawl further than others, so your plants and rows may need to be spaced wider than ours do.

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GROWING MUSKMELONS/CANTALOUPES SUCCESSFULLY UNTIL HARVEST TIME

  • If you’ve planted seeds in hills, thin the seedlings to the strongest two or three plants once they’ve reached 2 to 3 inches in height.
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  • If you’ve planted in rows – we usually prefer rows, but either way works well - thin your plants to about 1 every 24 inches.
  • Cantaloupe needs bees for pollination. If your area is light on bees, look on Craigslist or in the classified papers to see if there are any beekeepers willing to place hives on your property.
  • Make sure you don’t use pesticides – they’ll wipe out the bees. Also, as this is about growing cantaloupe organically, we’ll give you other suggestions in the “Pests” section below for dealing with bad bugs.
  • You can trellis cantaloupe if you have a very small garden, but you may need to support your fruits with a “fruit sling” (we use old nylons).
  • If you’ve properly prepared your soil using plenty of compost/composted manure, you shouldn’t really need to add fertilizer during the season, but you can side-dress with composted manure mid-season if your plants need more nutrients.

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MULCHING & WEEDING

  • We’ve already discussed black plastic as a mulch. It helps warm the soil and it suppresses weeds. However, you will need to use drip irrigation with black plastic as overhead watering simply won’t work.
  • It’s best to lay out your drip lines before laying down the plastic, then make sure you lay the plastic down in the heat of the day and stretch it as tight as you can over the rows.
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  • Organic mulches like woodchips or straw can also be used when growing cantaloupes, but don’t apply organic mulches until soils are warmer than 75°F.
  • Applying organic mulches too early keeps the soil cool, resulting in slow growth and shallow rooting.
  • If you’re not mulching and have to use manual weed control methods, be careful to not pull weeds around the base of your muskmelons or you may harm the shallow roots.
  • We cut off the weeds close to the plants with scissors to allow the cantaloupe plants to gain the upper hand over weeds without harming the plants.
  • Early in the season, I find it’s easy to control the bulk of the weeds by rototilling between the rows, and later in the season you can just pull the large weeds that’ll poke up between the vines.

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WATERING MUSKMELONS/CANTALOUPES

  • After planting, make sure you soak your seed area well, but don’t drown the seeds or seedlings.
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  • While drip irrigation is desirable, not everyone can afford it. If you have to use overhead watering like we do, make sure you do it early in the day so the plants dry out completely by noon.
  • We haven’t tried it, but we’ve heard that furrow irrigation is also very effective.
  • Watering early or using drip systems will help prevent foliage diseases that are common in squash family plants.
  • As it gets late in the season, and the muskmelons are about the size of baseballs, decrease watering; this helps the fruits to mature and prevents the fruit from splitting.

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COMPANION PLANTING AND ROTATION CONSIDERATIONS

  • Good companions for growing cantaloupes include:
  • Beans, which supplement your garden with nitrogen that it absorbs from the air.
  • Radishes, which are reputed to protect your muskmelons from squash borers, carrot flies, cucumber beetles, and leaf miners – these pests like radish leaves best, but don’t really harm radish plants.
  • Mint is said to help control ants, aphids, flea beetles, and rodents.
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  • Onions ward off fruit tree borers, weevils, aphids, rust flies, moles, and some root nematodes.
  • Marigolds and Nasturtiums repel bugs and beetles away from your muskmelons. They also attract bees which help to pollinate your cucurbit flowers.
  • Oregano is also said to benefit squash by keeping away some pests.
  • Corn is a great companion for squash family plants including muskmelons/cantaloupes. Corn produces lots of pollen and attracts beneficial pollinating insects.
  • Corn also provides shade to the melons in the afternoon heat, and the melon vines and leaves lessen weeds and preserve soil moisture.
  • A bad companion for melons are potatoes. Potatoes inhibit the growth in melon plants.
  • You don’t necessarily need to rotate melons annually unless you’re having issues with verticillium wilt, fusarium rot, or mosaic virus.
  • Because summer and winter squash, cucumbers, and melons are of the same family, though, it’s a best practice to rotate your plants to a different area next year.

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WHEN TO HARVEST

  • Cantaloupes/Muskmelons separate from the vine when ripened, unlike watermelons and other cucurbits.
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  • When you notice that your melons have changed to a yellowish or tannish color from their normal greenish color, and that the skin has gotten rougher and duller in appearance, your melons are close to ripe.
  • When the base of the stem appears to be cracked, lift the melon up and if the vine separates easily, the melon is ripe. The underside will also usually have a pale yellow appearance.
  • If your weather is hot, harvest the melons daily; if temperate, every other day should be fine.
  • Take care when harvesting not to damage the cantaloupe vines.

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SAVING CANTALOUPE/MUSKMELON SEEDS

  • Once your melons are fully mature and separate from the vine on their own, the seeds will be ready to harvest.
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  • Note that you cannot save seeds from hybrid varieties – not to be confused with GMO seeds. These seeds are cross-pollinated with other varieties to create disease resistance but cannot be used for any further cropping.
  • So, if you’re growing what is now termed a “heritage” seed, you’re good to go. Just scrape the seeds out of the muskmelon, wash them in a bowl of warm water, and scoop the clean seeds onto a dry towel and let them sit in a warm, dry area for about 3 days.
  • Store the seeds in a cool, dry place for next years garden. Placing the seeds in a zip lock-style plastic bag and freezing them is a great way to preserve these seeds as well.

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MELON STORAGE

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  • We’ve had very good results placing our harvested cantaloupes in the fridge for up to 2 weeks at about 40° to 45°F.
  • You can freeze cantaloupe after scraping the seeds, removing the skin, and cubing it. I like it fresh though so I don’t do this myself.

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PREVENTATIVE AND NATURAL SOLUTIONS TO COMMON PESTS

  • Aphids are a common pests that can be found on the undersides of your muskmelon leaves. You’ll know they’re there if you see leaves turning yellow and crinkling or curling.
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  • Aphids suck the juice from your plant leaves and leave a sticky substance behind. The only beneficiary of this process is ants, who harvest the sticky sweet stuff.
  • The best solution to aphids is to import ladybugs to your garden. They feed on aphids and are very effective in ridding your plants of these little green, gray, or brown bugs.
  • Another solution is to “wash” them off with a hose and high-pressure spray nozzle or an organic insecticidal soap.
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  • Cucumber Beetles are a striped beetle that is about 3/16″ in length, greenish yellow, with three black stripes running down its back.
  • The spotted cucumber beetle is pretty much the same but with a dozen spots on its back.
  • Regardless of what these beetles look like, they’re pretty nasty pests that eat your cantaloupe/muskmelon plants and spread bacterial or verticillium wilt to your plants.
  • To prevent these beetles from getting to your plants, you can use row covers before your plants flower to keep them away from your plants.
  • If the problem gets too severe, you can use organic pyrethrins or organic rotenone to deal with these critters.
  • Pickleworms are nasty little worms that come from ugly moths. These guys don’t mess with the leaves; they go straight for the fruit.
  • Row covers early in the season are effective at keeping pickleworm moths away from your cucurbits – squash, melons, and cucumbers.
  • One effective remedy for pickleworms is powdering your plants with diatomaceous earth.
  • Food grade diatomaceous earth, which is composed of powdered fossilized algae, possesses razor sharp edges which are innocuous to most animals but fatal to insects.
  • When insects such as slugs, thrips, fly maggots, aphids, grubs, caterpillars, or mites ingest diatomaceous earth, it punctures their guts and they die from dehydration.
  • You do have to keep the powder dry though or it doesn’t work. You’ll have to re-apply after watering or a rain.
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  • Squash Bugs are probably another prevalent pest. They suck the sap from your cantaloupe plant leaves, leaving them initially speckled; then the leaves wither and die.
  • Controlling squash bugs is easier if your soil has lots of nutrients and your plants are healthy.
  • Get rid of anything around your garden, such as old boards or anything they can hide under during the winter.
  • It also helps to rototill or turn under your garden in the fall to eliminate places these bugs like to hide in.
  • To get rid of the bugs, hand-picking usually works in a garden as it’s not so large as to take more than an hour or two per week for a few weeks in the summer.
  • When you pick these bugs and nymphs, have a pail of soapy water to drop them into…the soap breaks the capillary action of water so the bugs immediately sink and drown in the water.
  • If you find eggs attached to the underside of leaves or stems, simply crush the eggs.
  • Lay a board or two in your muskmelon patch overnight…the bugs will congregate under the boards at night. In the morning, lift the board and capture the bugs and drop them into the soapy water pail.
  • Organic compounds such as rotenone and pyrethrins are also effective if you have a heavy infestation of these varmints.

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ENVIRONMENTAL FACTORS

  • Muskmelons/Cantaloupe will sometimes be flavorless. This can be caused by cool weather or poor soil nutrients. Or picking the melons before they’re ripe (this is really common if you purchase cantaloupe at the supermarket).
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  • Smooth rinds often are caused by cool weather. These melons will often also have poor flavor as well.
  • To prevent lack of soil nutrients that causes lousy-flavored fruit, pay close attention especially to your soil’s potassium, magnesium and boron level.
  • Another problem we touched on earlier was poor fruit setting. This is caused by lack of pollinating insects in your area.
  • As I wrote above, you may be able to find a local beekeeper to put a hive or 2 on your property, or you can hand pollinate. Wet weather or plant crowding can also have a negative affect on pollination.
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  • Fusarium wilt is a soil-borne disease that affects cantaloupes. It results in the collapse of your plants when the weather is too cold and wet. Purchasing resistant varieties is probably the best solution to this disease.
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  • Powdery mildew can negatively affect your melon plants also; it’s whitish and powdery and grows on curcubit leaves and stems.
  • It is also caused by wetness, but warmth and humidity are the activator rather than cool weather and rain.
  • If the leaves are infected, they’ll usually die. If the infection is severe, it can kill the whole plant.
  • If you are able to, avoid overhead watering. If not, water early in the morning so the plants can dry out by noon or so.
  • If you keep insect pests under control and spray your vines and leaves with a compost tea solution or a baking soda solution, you most likely won’t have an issue with this disease.
  • Other solutions include organic sulfur sprays or a weak solution of milk and water (9:1).
  • If you spot any of this mildew, destroy your vines at the end of the season and rotate your cantaloupes to a new area next gardening season.
  • The best prevention is to plant resistant varieties of muskmelons/cantaloupes.
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  • Downy mildew is a leaf disease and is caused by a fungus with a long Latin name. If you really want to know the name, let me know and I’ll copy and paste it in a reply.
  • This mildew usually isn’t a problem unless you have a cold spell in the 45° to 55°F range for a month or longer.
  • The mildew shows up initially as yellow patches on your squash plant’s leaves, then turns brown or tan with gray or white downy fuzz below it. Then it progresses to black patches and the leaves and sometimes the plants shrivel up and die.
  • To prevent downy mildew, grow squash varieties that are resistant to it.
  • Also, allow space between your plants so they don’t stay wet too long.
  • And if the conditions appear favorable for the disease to appear (i.e. a long cool and rainy spell), spray your leaves with a compost tea. To make the tea, put compost in a bucket and fill it with water; when it settles out, fill your sprayer with the brownish water and spray your plants leaves with it.
  • Muskmelon seedlings may be affected by a group of fungi that cause “damping off.”
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  • Damping off fungi will attack the seeds, seedlings or very young plants and cause a type of rot to infect the roots or base of the plant causing sudden growth and collapse in usually (in our experience) under a day.
  • If you’re planting in trays, use sterile potting soil, sterile trays, and avoid using your gardens soil.
  • You can sterilize potting soil by getting it very wet and placing it in a metal container in an oven and heating it to around 160°F for about 30 minutes; the oven should be heated to around 200°F.
  • Use a meat thermometer to check the temperature; turn the oven down a bit if the temperature exceeds 165°F.
  • Cool the soil to at least 90°F before planting your seeds in it.
  • Also be aware that too much moisture is often part of the cause of seedlings damping off.
  • Water your plants with warm water as cool temps tend to encourage damping off fungi.
  • And the last one we’ll deal with are Leaf Spots and Fruit Rot. These are caused by fungal disease and include rotting fruit, lesions on the vines, holes in the leaves, and brown-colored spot on the leaves.
  • Rotating your crops to new areas on a 3 to 4 year rotation will help alleviate these problems.
  • Reducing moisture can help also – using drip irrigation or watering early is helpful. Don’t crowd your plants. Keep the melon patch weed free.
  • To avoid these diseases don’t grow melons in an area where any member of the squash family has been grown for 3-4 years.

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4 Responses to “How To Grow Organic Muskmelons/Cantaloupes”

  1. tomika hines Says:

    Im growing cantaloupe in a small pot and its only been 5 days and shes already coming up…my question is howw long before i place it out doors?

  2. Jenny Says:

    Wait until the soil is well-warmed and there is no danger of frost. The highest percentage of growth occurs with this plant when the temperatures are between 77-80 degrees. Along with my watermelons and eggplants, they are the last plants I put out in my garden. I give them a full week of acclimating to the outdoors by putting them outside during the warmest part of the day and increasing the length of time outside each day. Having them in pots gives you an advantage to be able to acclimate them as long as you need to if the weather is not cooperating.

  3. Christine Says:

    Growing “Charentais Cantaloupe” in a container on a full-sun south-facing porch. It’s about 10 inches tall and it’s already starting to flower. Is this normal, or should I pinch the flowers off?

  4. Jenny Says:

    It’s normal. I would not recommend pinching the flowers off. It takes cantaloupe long enough to mature as it is; pinching off the flowers will only extend the time it takes to get a harvest. Depending on the length of your growing season (such as mine), it might prevent the chance of getting any mature fruit altogether!

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