Growing pumpkins can be a lot of fun, and very rewarding, for the home gardener. It’s exciting to see the transformation from stunning yellow to flowers, to green globes that seem to grow before your eyes, and then into the recognized bright orange pumpkins everyone knows and loves.
For people that don’t want a dedicated garden space, growing pumpkins in grow bags is a great alternative.
In this article, we are going to talk about everything you need to know about growing pumpkins in grow bags.
Let’s get started…
What is a grow bag?
I’m sure you’re wondering what the difference is between growing plants in potted containers and planting them in grow bags instead?
In case you aren’t sure what grow bags are, they are double layered, woven polypropylene (i.e. food safe plastic) bags that can be filled with potting soil and used as planting containers.
For starters, there is a huge similarity between the two growing methods: container gardening and gardening with grow bags are alternative methods of gardening without planting directly into the ground but using vessels holding potting soil instead.
Both are invaluable for gardeners who have limited space to work with, or someone who’s soil is really poor quality.
Grow Bags vs Containers – Why choose grow bags?
Besides the basic concept of the two being the same there are some incredibly important differences that actually make growing plants in grow bags better than using containers.
Grow bags have increased in popularity significantly due to their convenience and the better-growing conditions they foster.
The biggest complaint with growing plants in containers is that the plants become root-bound really easily, affecting and stunting the growth of the plant. This increases the chances of having issues with lack of oxygenation and water stagnation in larger pots with poor drainage.
Over time the roots become constricted and cannot absorb water or nutrients and there is potential for the stem to get compressed, causing structural problems.
When plants are grown in grow bags, they have a much healthier root system. As the roots reach the drier soil that is exposed to the air at the edges of the bag the roots “air prune” because they sense they are out of space.
Thus, preventing overgrowth and girdling. It also encourages a more fibrous root system
5 Tips On Growing Pumpkins In Grow Bags
If you are interested in growing pumpkins in grow bags, here are some great tips to help you get started!
Buy Your Grow Bags
Grow bags come in a variety of sizes to meet the needs of the plants you want to grow. Smaller bags hold about 3 gallons of potting soil and work well for herbs, and plants with short root systems such as garlic, radishes, and lettuce.
The most common sizes are 5 – 10 gallons; these work well for one or two plants of tomatoes, peppers, beans, squash, etc.
Specialty bags can be purchased for deep-rooted crops such as potatoes, and you can even buy grow bags that will hold up to 45 gallons of potting soil!
My bag of choice when growing pumpkins is something like this found online. It offers plenty of room for growth, great drainage and best of all it is reusable.
Fill with Potting Soil
One of the most important aspects of getting started with grow bags for growing pumpkins is to fill them with high-quality, potting soil.
Look for a commercial product that is light and airy in texture, consisting of peat moss, pine bark, and perlite or vermiculite.
Potting soil acts as a reservoir for moisture and nutrients around the roots of the plants, it provides “empty” space for air around the roots to allow them to breathe, and it supports the plants by anchoring the roots.
If you start by filling your pots with a poor-quality potting mix, it’s not going to hold moisture and nutrients, and it won’t have the right structure to anchor the roots while letting them get enough oxygen.
My choice for potting soil is Miracle Gro’s Vegetables and Herbs Soil.
If your growing season is short, it’s best to sow seeds inside in peat pots about a month before the last frost-free date in spring.
When the soil temps hit 70 degrees you can direct sow seeds or take your plantlets outside after they have been hardened off.
Seeds should be planted approximately 1” deep and can be spaced so that 4-5 seeds are in a single “hill” within a grow bag. Hills will help the soil warm more quickly and the seeds will germinate faster; plants should germinate within about a week of planting.
When the plants reach a couple of inches tall thin each hill, so they only have the best growing 2 or 3 plants.
After planting your plantlets or seeds in the grow bags, it’s time to move them to the best location for optimal growth.
Pumpkins love full sun and do best in a spot that will give them at least 6-8 hours of direct, unfiltered sunlight every day.
They also need plenty of space to stretch their vines. A typical hill of pumpkins – or in this case a single growing bag – needs 50-100 square feet of space to grow adequately.
One great benefit to using grow bags is how easy they are to move around. The bags themselves are incredibly lightweight and they come with sturdy, attached handles making the entire process easier.
Due to their porous nature, grow bags will require more water than even traditional plastic or terra cotta pots.
This is one disadvantage to using them over container gardening or traditional planting methods.
Give plants at least 1” of water per week, watering when the top of the potting mix is dry to the touch. One advantage to the grow bags is their porosity makes it so that grow bags are nearly impossible to over-water.
Any excess water applied to the pumpkins will simply leach out of the bag into the ground underneath it.
A common problem with containers is overwatering which leads to mold or fungal problems; this is avoided with grow bags.
If providing your grow bags enough water is an issue, consider installing an irrigation system that runs automatically via a timer, or incorporate a self-watering system that will slowly water as needed.
As with potted containers, you are going to need to fertilize the pumpkins in your grow bags slightly more often than plants put into the ground.
Pumpkins are extremely heavy feeders and require more fertilizer for optimal growth than many other garden plants. When the pumpkin plants are smaller fertilize with a high nitrogen fertilizer to encourage the runners/vines to grow.
Just before blooming begins, switch to a fertilizer high in phosphorus to boost blooming and pumpkin production.
Growing pumpkins in grow bags has many advantages over typical plastic or terra cotta containers, making them advantageous for gardeners who have limited space or don’t want to tear up their yard to create a traditional garden.
Grow bags help encourage a healthier root system which leads to stronger, more bountiful plants.
With the aforementioned tips, you can grow pumpkins in grow bags like a pro!