Growing Watermelon in Grow Bags: A Step-by-Step Guide
Watermelons in grow bags
Are you interested in growing your own watermelons but don't have much space or a proper garden?
Watermelons can be successfully grown in grow bags, a great alternative for small spaces and urban gardens.
In this guide, we'll teach you the benefits of using grow bags and how to plant bush-type or smaller watermelon varieties. Let's get started!
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What are Grow Bags?
Grow bags are an innovative and versatile gardening solution, perfect for those who lack space or want a more flexible approach to cultivating and growing plants themselves.
Made from breathable materials such as fabric, felt, or polypropylene, these portable containers allow for better aeration and drainage compared to traditional pots or garden beds.
Grow bags come in various sizes to accommodate a wide range of plants, from vegetables and herbs to flowers and small trees.
They are particularly popular among urban gardeners and those with limited outdoor space, as they can be easily moved, stored, or even hung on walls or balconies.
Overall, grow bags offer an efficient and eco-friendly option for nurturing a thriving garden in unconventional or restricted spaces.
Benefits of Growing Watermelons in Grow Bags
Watermelons are a delicious and nutritious summertime treat, but many people don't realize that they can be grown in grow bags.
Growing watermelons in grow bags are an ideal solution for those with limited space or who want to cultivate plants more flexibly.
Grow bags offer several benefits over traditional pots or garden beds, including:
Improved root development: The breathable material of grow bags promotes air pruning, preventing roots from circling and encouraging healthier root systems.
Better drainage: Grow bags offer superior drainage compared to traditional pots, reducing the risk of overwatering and root rot in watermelon plants.
Temperature regulation: The fabric of grow bags helps regulate soil temperature, keeping the roots cooler in hot weather and promoting optimal growth conditions for watermelons.
Space-saving solution: Grow bags can be easily moved or rearranged, making them an ideal choice for gardeners with limited space or those who want to grow watermelons on a patio or balcony.
Flexible sizing: Grow bags come in various sizes, allowing you to choose the right one for your watermelon plant's specific needs.
Easier maintenance: Grow bags make it simpler to monitor and adjust soil moisture and nutrient levels, ensuring your watermelon plants receive the care they need.
Eco-friendly option: Many grow bags are made from recycled materials and can be reused for multiple growing seasons, reducing waste and promoting sustainable gardening practices.
Cost-effective: Grow bags are generally more affordable than traditional pots or raised beds, making them an economical option for growing watermelons.
Materials Required
To get started growing watermelons from seed in grow bags, you'll need the following items:
- Watering can or hose
- Plant markers/labels
Here is an up close view of what watermelon seeds look like.
Here is the 10-gallon grow bag that I planted my watermelon seeds in.
Watermelon Varieties for Grow Bags
When people think of growing watermelons they think that you need to have a large plot of land or a large garden to do so. But this isn't true! Several bush-type or compact varieties of watermelon can be grown in grow bags.
These varieties of watermelon have shorter vines and occupy less space, growing up to only 3 feet in length, in contrast to some other vining watermelon varieties that can grow up to 10 feet. But don't worry you will still have plenty of watermelon to harvest. Each vine will produce 2 to 3 watermelons each.
I opted to cultivate the Bush Sugar Baby watermelon, a compact variety with deep green skin and succulent red flesh bursting with flavor. These babies clock in at a perfectly portable 10-12 pounds each, making them the go-to pick for anyone looking to indulge in a little summertime sweetness. Trust me, once you try this type of watermelon, you'll be hooked for life.
Looking for some more homegrown watermelon options? Here is a list of popular watermelon plants to grow in grow bags:
Golden Midget
Moon and Stars
Orange Sweet
Crimson Sweet
Jubilee
Early Moonbeam
Solitaire
Jade Star
Millennium
I decided to try growing Bush Sugar Baby Watermelon.
I choose to grow Bush Sugar Baby watermelon because it can be grown as container plants and is a compact variety.
What Size Grow Bag for Watermelon?
A minimum of a 10-gallon grow bag is an ideal size for growing watermelon, especially when you're planting seeds of compact or bush-type varieties. This size provides enough room for the roots to develop and ensures proper nutrient absorption.
However, if you have more space available and want to grow larger watermelon varieties, you might consider using a 15 to 20-gallon grow bag for better results.
I used a 10-gallon grow bag for my watermelon which has a height of 12 inches and a diameter of 16 inches.
When to Sow Watermelon Seeds in Grow Bags
Watermelons are a warm-weather crop and should be planted after all danger of frost has passed and the soil temperature is consistently above 70°F. To ensure success, it's important to sow watermelon seeds at the right time.
The best time to sow watermelon seeds in grow bags is usually about two weeks after the last frost date for your area. Planting too early can lead to poor germination and seedlings that don't survive cold weather or damp conditions.
If you live in an area with short summers, consider starting your watermelon seeds indoors for about 4-6 weeks before transplanting them outdoors.
How to Grow Watermelons in Grow Bags
It's time to start growing your watermelons now that you have determined the type of watermelon to grow and the appropriate size of the grow bag needed.
Prepare the Grow Bag
It is important to choose its location carefully, while you can move it if needed, the best case scenario is to choose the spot where you want your watermelons to grow and leave it there.
It should receive plenty of sunlight (at least 8 hours a day) and be in an area sheltered from strong winds. Once you have chosen the right spot, unfold the grow bag.
Fill Your Grow Bag
Fill the grow bag with a high quality potting mix and soil, leaving a few inches of room at the top to accommodate watering. Use a high-quality, well-draining potting mix that contains organic matter.
I used Miracle Gro's moisture control potting mix because I have had success with it in the past and I can buy large bags of it.
You will need a lot of potting mix for a 10-gallon grow bag.
Sow the Watermelon Seeds
After the last frost, sow 3-4 watermelon seeds directly into grow bags bag, about an inch deep. Space them approximately 3 inches apart.
Always read the seed packet and follow its sowing instructions for the best results.
Cover and Water
Gently cover the seeds with soil and water the area thoroughly. Use a watering can with a gentle shower to avoid displacing or uncovering the seeds.
Keep the soil consistently moist, but not overly wet. Watermelon seeds can easily rot with excess water.
Watermelons require consistent watering throughout their growing season; aim for 1-2 inches of water per week during dry spells. On days over 85°F, water twice a day.
Unfortunately, one downside of grow bags is that they dry out quickly, so keep an eye on the soil.
Monitor Seedlings
In 7-14 days, watch for seedlings to emerge. Make sure they receive adequate sunlight, aiming for 6-8 hours per day.
1st Watermelon seedling!
Thin Out Seedlings
Once seedlings have sprouted and have 2-3 sets of true leaves, thin them down to one to two healthy seedlings per bag.
Keep only the strongest and healthiest ones. Remove the rest by snipping or pinching them at the soil level.
Fertilize
Your favorite fruit is a HEAVY feeder and needs some TLC to grow big and juicy. Don't worry, though- we've got the inside scoop on how to nourish your watermelons like a pro.
Watermelons require different types of nutrients at various stages of their growth.
Before flowering, watermelons prefer nitrogen-rich soil. However, be cautious not to provide your watermelon vines with too much nitrogen, as it can lead to excessive vine growth without bearing many fruits.
During the fruit development stage, watermelons require higher amounts of phosphorus and potassium for healthy and well-formed fruits.
Nourishing your watermelons as they grow can be simple. Add two tablespoons of granular organic fertilizer with higher phosphorus to the soil every month for a boost.
If you are growing watermelons in containers, you may consider using a liquid organic fertilizer that contains a higher amount of phosphorus. Here is my full review of Neptune’s Harvest Fish and Seaweed Fertilizer.
This is the fertilizer I used on my watermelons and I highly recommend it. It has a 2-3-1 ratio and has a blend of fish and seaweed.
For the best results, start fertilizing every three weeks once the seedlings sprout their first true leaves.
This will ensure that your watermelons receive the necessary nutrients for vigorous growth and abundant fruit production.
Provide support
For the best results, provide support for your watermelon vines with a trellis or stake. You can purchase trellises and other gardening supplies at Dollar Tree.
Watermelons have a natural inclination to coil their tendrils around a trellis or stake. Assisting their growth by gently guiding the vines around the stake or trellis can prevent them from spreading across the ground and reduce the risk of diseases. This simple practice not only promotes better watermelon cultivation but also enhances aesthetics and minimizes potential issues.
You can see the tendril is curling around the trellis.
Monitor for Pests and Disease
Check regularly your container watermelon, for common pests such as aphids and spider mites, and watch for signs of diseases like powdery mildew.
Identifying any problems early and taking the appropriate action can mean the difference between healthy watermelons or none at all.
I noticed some pests including aphids were starting to eat the leaves on my watermelon plant. I put sticky glue traps near the leaves and that seems to have helped. The glue traps are nontoxic and waterproof. When they fill up, you can easily replace them with fresh ones.
I placed sticky traps near the leaves to deter pests like aphids.
Harvest
Once the plants reach maturity, it's time to harvest your watermelons. Depending on the variety you are growing, they should be ready for harvest about 75-92 days after planting.
When harvesting, use pruning shears or a sharp knife to cut them.
Some signs that your watermelon is ripe for the picking include: the tendril opposite the watermelon fruit should also be brown, a yellow spot where the watermelon touches the ground, and a dull thud sound when tapped.
Planting and Care Tips for Growing Watermelons in Containers
Here are some tips to help you maintain a healthy watermelon plant:
Support the vines: Install a trellis, cage, or other support structure to help manage vine growth and save space. Train the vines to grow vertically, which will also improve air circulation and reduce the risk of diseases.
Pollination: If you're growing watermelons in an area with limited pollinator activity, consider hand-pollinating the flowers to ensure fruit set. Use a small paintbrush or cotton swab to transfer pollen from male flowers (with thin stems) to female flowers (with a small swelling at the base).
Prune selectively: Prune the vines by removing any dead or diseased leaves and pinching off suckers that compete with the main vine for nutrients and space. This will encourage the plant to put more energy into fruit development.
Stop watering: To make watermelons taste sweeter, you should avoid watering them two weeks prior to harvesting. This will result in less water in the soil and more sugar concentration in the fruit, which makes it taste even sweeter.
Frequently Asked Questions About Growing Watermelon in Grow Bags
How do you know when your watermelon is ripe?
Some indicators include the underside turning yellow or cream-colored, and a brown tendril opposite the fruit, also the days to maturity listed on the seed packet.
How often should I water my watermelons in grow bags?
Watering frequency is critical for success when growing watermelons in containers. Aim to provide 1-2 inches per week and more during dry spells and when there is extremely warm weather.
What size grow bag do I need for watermelons?
For bush-type/small watermelon varieties, a 10-15 gallon grow bag is ideal.
Can I grow watermelon in a 5-gallon bucket?
A 10-15 gallon grow bag is ideal for bush-type/small watermelon varieties because they need space for their root system to thrive. A 5-gallon bucket may be too shallow for them.
What month is the best time to plant watermelons?
The best time to plant watermelon in containers is usually when the weather has warmed up and there is no chance of frost.
Should you grow watermelon from seed or transplants?
Watermelon plants do better when direct sown however, you can start them indoors about 4 -6 weeks before the last frost and then transplant them outside if you have a short growing season.
Watermelons in Grow Bags
Growing watermelons in grow bags are a great way to enjoy this summertime favorite, even if you don't have a lot of space for traditional garden beds.
With the right technique and variety selection, you can be rewarded with plenty of sweet melons all season long. So get growing watermelon plants and enjoy the fruits of your labor!
