How to Grow Cantaloupe and other Melons in Northern Climates

Introduction

Melons (Cucumis melo) include cantaloupe, also known as muskmelon for its “musky” taste, honeydew, and other less well-known melon types. Cantaloupes usually have orange flesh and a cork-like net on their skin, although some varieties have smooth skin. Honeydew melons usually have green flesh and smooth skin, but you can now find orange-fleshed honeydews. Other types of melons include the French Charentais, Canary, Galia, Crenshaw, and Piel de Sapo. Melon crosses between different types also exist. Although watermelons share a similar name, they are a different species (Citrullus lanatus), and I will not cover them here. For a list of commonly available melon varieties, including their days to maturity, hybrid or open-pollinated status, color, disease resistance, and more, please see my previous blog post.

​Many consider Charentais or French melons to be one of the best-tasting melons, though they are usually smaller, without netting, slower to ripen, and prone to splitting. Charentais melons have a unique gray-green rind that turns yellowish when ripe. Canary melons are more common in Asia and have hard yellow rinds with white or pale green flesh. They taste a bit like a honeydew-cantaloupe cross and are sometimes called a “winter” melon because they take a long time to mature, and their hard rind allows them to store longer than most melons. Galia or tropical melons are a hybrid of cantaloupe and honeydew that originated in Israel. They have a netted rind but no ribbing, with pale green flesh, a tropical flavor, and a banana-like aroma. They are ripe when they get orange-tinted skin with a musky aroma. Crenshaw melons are oblong with pale-yellow skin. Their flesh is pale orange, sweet, and aromatic. Crenshaw melons are crosses between cantaloupe and casaba melons. Casaba melons have wrinkled skin that is yellow with white or green flesh. The flesh is mildly sweet with hints of cucumber and citrus. Piel de Sapo melons are most commonly found in Spain and have yellow and green mottled skin. They are sweet-tasting and aromatic.

How To Grow Melons

​Most melons grow best in warm, dry climates with long growing seasons, which can make them challenging to grow in northern climates. The top melon-growing states in the United States are Florida, Georgia, California, Texas, and Arizona, which are far from where I live in central Wisconsin. However, wide varieties of melons do well in cooler climate conditions, and there are also some tips and tricks you can use to increase the success of growing ripe, sweet melons.

​Melons require high amounts of nitrogen and do well with aged manure or compost. Plant after any danger of frost is gone, when the soil temperature reaches 70°F, and preferably when there are no more nights in the 40s. I can still get occasional nights in the upper 40s in July and August, so I usually plant in the first half of June, regardless. You can use frost covers to help warm up beds or use plastic sheeting around the hills to keep the soil warmer. I have been trying to use less plastic in my garden, so while I do still use frost covers (which can still add plastic to the environment) I avoid plastic for mulching. If you do use frost covers or other row covers, be sure to remove them once the flower buds start opening, or they will not get pollinated. Melons like moist but well-drained soil with a neutral pH of about 7.0. They will not do well with overly sandy soil that dries out too much or with standing water. Stop watering about a week before the melons ripen, as too much water can make their flavor bland.

Plant seeds or transplants about 2-3 feet apart in rows 6 feet apart. Some varieties are more compact and can handle rows closer together. I plant my melons in raised beds and so do not incorporate rows, instead I keep them about 2-3 feet apart, but I also like the “Minnesota Midget” variety, which is more compact than many others.

Melon Selection

​Pick melons that have shorter days to maturity and do well in cooler climates with shorter growing seasons. Honeydew, for example, traditionally needs a long, hot, dry growing season, and typically would not grow well in northern climates. But you can now find varieties that have been selected to be easier and faster to grow. To find these varieties, I like seed companies from the north that sell hybrid varieties, such as Johnny’s Selected Seeds, Fedco Seeds, High Mowing Organic Seeds in the northeast, or Territorial Seed Company in the northwest. One of my favorite cantaloupe varieties is “Minnesota Midget”. These melons have a short number of days to maturity, around 60-70 days. Remember that days to maturity are an estimate based on optimal growing conditions. If you have an unusually cool or rainy summer, you may see harvest delayed by a couple of weeks. I try not to grow any melons with over 90 days to maturity, as there just isn’t enough time in my growing season. I usually cannot plant my melons until the first week or two in June, which does not leave enough time for full maturity if I get an early frost in mid-September. It also does not help to plant earlier if your soil has not warmed up or nighttime temperatures are still cool, as the seeds may not germinate or the plants may not thrive.

Raised Beds

​I prefer to grow my melons in raised beds. There are several advantages to raised beds, besides ergonomics. Raised beds warm up faster in the spring, and the soil remains warmer all summer than in-ground gardens. Raised beds also drain better, both of which help grow melons. I like to use soaker hoses in my raised beds to keep the ground evenly moist without getting water on the leaves, which can promote fungal diseases.

Start Indoors

I have found that if I start my seeds indoors even two weeks before planting outside (do not start more than 1 month before planting), I get better melon harvests. I get better germination inside with a heating mat than outside in the soil that may not have warmed up enough. Starting indoors also keeps birds and other animals from eating the seeds, and it gives the seedlings 2-4 weeks to grow before being subjected to pest and disease pressure. The key is to grow the seedlings in biodegradable pots to minimize root disturbance when planting outside. The downside to this approach is that you need to harden off your seedlings before planting outside so they get used to the sun and wind.

Pests and Disease

​My biggest problem growing melons, other than my short season, is voles (or other rodents) eating the melons. One solution I plan to try this year is placing the ripening melons on a brick or other surface to get them off the ground. I hate picking a melon and then finding a hole in the bottom.

Another pest problem I have had is the striped cucumber beetle eating the leaves, particularly after they first emerge, which can kill young seedlings. I avoid this by starting my seeds indoors, so the plants are larger and better able to tolerate pest damage, or by using row covers when I first plant them out. You can also spray the beetles with an insecticide, but I never spray once my plants are flowering, as this can kill bees and other beneficial pollinators. Another option is to spray with Surround, which is a kaolin clay mix that coats the leaves and reduces insect feeding. This is an organic option, but my biggest hurdle with this spray is that it tends to clog the sprayer. You can also use sticky traps, but I tried this once with my squash and accidentally caught a bird. I will never use sticky traps outside again. The striped cucumber beetle can also spread bacterial wilt, so if you can control the beetles, the disease should not be a problem.

​The main disease issue I have had is powdery mildew, but I usually find that this is only a problem late in the season and does not usually affect my ability to harvest ripe melons. You can use fungicides, such as sulfur or even milk, but wide varieties of melons have resistance to powdery mildew, so choosing one of them to grow is easier if you do not have your heart set on a specific variety that is susceptible to powdery mildew.

​Other diseases you may experience include Alternaria blight, Fusarium wilt, Papaya Ringspot Virus, Watermelon Mosaic Virus, and Zucchini Yellow Mosaic Virus. There are many different ways to deal with these diseases. For example, fungal diseases can be prevented (more easily) or treated with fungicides, increase plant spacing to increase airflow, do not water overhead, or plant disease-resistant varieties. Insects or mechanical damage to the plant always spread plant viruses. So if you can prevent striped cucumber beetles (see above), you can prevent viral diseases. Another option is to plant virus-resistant varieties. For a list of disease-resistant melon varieties, please see my earlier blog post.

Harvest

​Once your melons begin to ripen, you want to check them every day. Melons can quickly move from ripe to overripe. Most melons are harvested when their rinds turn yellowish, and they are at “full slip,” which means a gentle tug causes them to slip from the vine. Some melons, such as Galia, Charentais, Piel de Sapo, and honeydews, are often better if harvested a little before full slip, at “forced slip.” Most melons do not store well and are best if eaten within a few days.

References and Resources

1. Cox, Jeff. How to Grow Vegetables Organically. Rodale Press, 1988.
2. Melon – Key Growing Information. Johnny’s Selected Seeds. https://www.johnnyseeds.com/growers-library/vegetables/melons/melons-key-growing-information.html?_gl=1*1qumhle*_up*MQ..*_gs*MQ..&gclid=CjwKCAjwspPOBhB9EiwATFbi5GBjDDQLNN2Twindbh6Cq28n3j8iSkL9LDuXumyJbMlyTQntwFNQwBoCQmEQAvD_BwE&gbraid=0AAAAAD_WiV0QQDtRrhuX4f6MhYiBz7eEF
3. Melons. Agricultural Marketing Resource Center. August 2021. https://www.ers.usda.gov/data-products/charts-of-note/chart-detail?chartId=76793
4. Melons. Fedco Seeds. https://fedcoseeds.com/vegetables/melons