Skip to Content

Growing Watermelon In An Earthbox – How It Works

There’s nothing quite like a summer watermelon fresh from your garden. Like most garden produce, the sweetness and complex flavors of a home-grown watermelon are a far cry from the watery and often flavorless watermelons you can get at the store. 

These fruits are one of the best treats you can grow, but they’re also garden hogs. Watermelons can sprawl and grow over wide swathes of your garden, and they don’t share space very well, even with other melons or smaller fruits and vegetables. 

Growing your watermelons in an Earthbox is an excellent alternative to garden growing. You still get all the flavor of a garden melon, which means that you can grow your watermelons next to your other garden plants or grow them inside in a well-lit room. 

You need to change how you grow your melons a little to help them adapt to Earthbox growing and ensure you get a healthy harvest. This guide will walk you through the details, so you’re prepared for a fantastic harvest even the first year you grow watermelons. 

What Is An Earthbox? 

Earthboxes are specially designed growing containers designed to make it easier to grow vegetables even when you don’t have space for an in-ground garden. They’re suitable for patio growing or growing in yards where you can’t plant directly in-ground, and they even make it possible to grow your fruits and vegetables indoors. 

A combination of aeration screens and sub-watering systems that make water available from below make Earthboxes stand out from other growing containers. 

An overflow drain also helps protect your fruits and vegetables from overwatering, making Earthbox growing easy and effective for gardeners of all ages and skill levels. 

These containers are perfect for smaller watermelon varieties and almost any other fruits and vegetables you want to grow in them. 

What Varieties Of Watermelon Are Best For Earthbox Growing

The original Earthbox is a good fit for smaller watermelon varieties. Sometimes called personal watermelons (and trust us, you won’t want to share your first garden-grown watermelon), these smaller watermelons are easier to grow and don’t take up as much space as their larger cousins. 

Here are some of the best small watermelon varieties you can grow in an Earthbox: 

  • Sugar Baby (Sweet, small, easy to grow) 
  • Mini Yellow (Sweet, with yellow flesh)
  • Yellow Baby (another yellow variety, great if you want a thinner rind) 
  • Blacktail Mountain (fast-growing and larger than many mini-watermelons)
  • Sweet Beauty (More elongated than most, perfect for sharing) 
  • Moon And Stars (Thicker rind perfect for pickling, smaller vine, red, orange, or yellow flesh) 
  • Crimson Sweet (best known for its sweeter than average taste and bright red flesh) 
  • Mini Love (Slightly smaller melons, perfect for eating in one sitting) 
  • Golden Midget (smaller personal-sized melon with yellow rinds) 

None of these vines will produce overly large watermelons, which makes them easier to grow and helps ensure they produce flavorful melons. Plus, these perfectly sized melons are suitable for sharing or eating alone. 

Grow enough vines, and you can even throw a barbecue with a melon for every guest! 

How To Care For Growing Watermelons

Taking care of watermelons isn’t difficult, but they are relatively particular vines. They need good growing conditions throughout the growing season and will throw tantrums if they aren’t kept in the right conditions. 

Here’s what you need to know about growing watermelons in an Earthbox. 

What Kind Of Soil Is Best For Growing Watermelons? 

Watermelons are picky about their soil or potting mix. They need lots of water but don’t like having wet roots. 

That’s part of what makes an Earthbox a good option. The under-soil water reservoir helps ensure there’s always plenty of water available while keeping the water away from the roots and protecting them from the most common root problems. 

As a result, you need a potting mix made with sphagnum moss and spongey and loose. Well-aerated soil is a must for healthy watermelons, but the sphagnum moss helps pull water out of the reservoir for more efficient growing. 

Avoid soil mixes with soil or clay; only use a small amount of compost if you use any. Too much silt can clog the watering system, and too many nutrients or rich soil may lead to root burns or compacted, poorly-aerated soil. 

Do Watermelons Trelis Well? 

Yes! Their vertical growing system is the best way to grow watermelons in an Earthbox. That way, the plants get a lot more space to grow. 

Wait until the vines are long enough to move easily, then place the tip against the Earthbox trellis netting. The watermelons will grow up on the trellis on their own or with very little encouragement from there. 

Growing vertically isn’t just good for saving space; it can also make your watermelon vines a little more productive and help them hit fruiting season a little sooner than they normally would. 

Protecting Your Growing Watermelons

Watermelons are a heavy fruit; unfortunately, even the smaller varieties can detach from the vine if they aren’t properly protected. 

To grow watermelons vertically, you need to give the watermelons a small hammock to help support the weight of the fruit. 

Cheesecloth, old t-shirts, and soft fabrics make good hammock materials. Tie either end of the material to the trellis, and check your watermelons daily to ensure they stay in the hammock and don’t detach. 

It’s also important to make sure the watermelon hammocks don’t touch the vine connection, or they might cut off some of the circulations into the watermelon. 

How To Fertilize Your Watermelon Vines?

Watermelons are nutrient greedy, just like water greedy, but you need to be careful about fertilizing too much when growing in an Earthbox. 

It’s a good idea to add a small amount of nitrogen-rich fertilizer to the Earthbox once your watermelon plants start vining. The extra nitrogen will help your watermelons grow leaves and stem faster. 

Later, when your watermelon vines start producing melons, you’ll want to switch to a fertilizer with more potassium and phosphorous and less nitrogen. That will help you grow watermelons with richer, sweeter flavors. 

Just make sure you use less fertilizer than you would in a garden. Roughly 1/2 the usual amount is plenty in an Earthbox because the nutrients won’t be washed out of the soil. You should also only fertilize 2-3 times through the growing season – More than that, you risk burning the roots and lower stems of your watermelon vines. 

How To Tell When Your Watermelons Are Ready

Watermelons can look ripe for a long while before they’re ready to be harvested. 

You might not get the usual garden spot on the melons for these varieties growing vertically. However, if the melon is going to develop a garden spot, it will be where the melon rests on the hammock. A bright yellow spot is a good sign of ripe melon, while white or tan spots mean that the melon isn’t ready for harvesting. 

You should also look for the melon’s stem to start turning brown and for the leaf or leaves closest to the melon to turn brown. 

Watermelon Diseases And How To Deal With Them

Watermelons grown in containers are less likely to catch diseases than watermelons planted directly in the ground. However, you should still be prepared to deal with some of the most common diseases affecting your watermelon harvest. 

Alternaria Leaf Spot: 

This fungal disease will create small yellow-rimmed spotty holes in your watermelon’s leaves. It can be treated with most garden fungicides. 


Anthracnose causes brown spots on the melons and can be prevented with preventive fungicide treatments or eliminated with regular fungicides. 

Gummy Stem Blight

Gummy Stem Blight is another fungal issue and can sometimes be treated with normal fungicides if you catch the disease early. However, if the disease resists treatment, it’s important to remove the watermelon and replace the growing media in your Earthbox before planting another melon. 

Questions & Comments For Me?
Write To Us At: 19046 Bruce B. Downs Blvd. # 1199 Tampa, FL 33647