Questions and Answers About Growing Plants in Grow Bags

Questions and Answers About Growing Plants in Grow Bags

By Michael Jenkins

1) There are mushroom/mold/green stuff on the outside of my grow bags or on the soil in them! What do I do?

We know that an unwanted guest growing near your plants can be unsettling, but it’s important to remember that these are almost all harmless to your plants. We’ll take them topic by topic to explain what they are and what you should do about them.

  • Mushrooms are not only harmless to your plants, but they’re a good sign that your soil is healthy. We’ve written a blog about what mushrooms mean for your soil, so give that a look for more details. Many mushrooms aren’t safe to eat so you may want to remove them to avoid accidentally mixing them with your veggies, but they won’t harm the plants or soil just by growing there.

  • Moss and mold are both likely harmless. Mosses are just plants that love shade and water, and they indicate that those conditions are present for your plant. You can try allowing the soil to dry out a bit and moving it to a sunny spot to help eliminate both moss and mold, but those conditions may not be the best for the plant growing in that particular grow bag. You can clean your grow bag using the steps outlined here or—when the bag is empty—by rinsing it off with a hose and then scrubbing gently with warm soapy water before rinsing again. Make sure to let the bag dry thoroughly before storing it away, or you may find mold and mildew waiting for you when you get back. Molds growing directly on your plants may be a cause for concern, so please check out these sources for more information.

  • A green slime or thin gritty green layer on the grow bag or soil is most likely algae, and can be treated the way you would moss or mold.
  • We do not recommend machine washing empty grow bags, particularly our potato grow bags. Our bags are tough and designed to withstand many years of use, but the heat and stress of a washing machine may shorten their lives somewhat or damage the Velcro attachment in the case of our potato grow bags.


1.5) How should I clean my grow bags?

Here’s a quick recap on how to clean grow bags with plants or soil still in them:

  • Fill a small basin with a solution of baking soda or vinegar mixed with water.
  • Use a soft-bristled scrub brush to lightly scrub the pot, removing build up or moss.
  • Then let the container air dry.

For empty grow bags, please refer to Question 1 in this list for more details.


2) How many peppers/eggplants/cucumbers/carrots/etc can I plant in each grow bag?

It’s a little tricky to answer this, as it does depend in part on the varietal of each plant. Generally speaking, we like to allow 5 gallon/20 liters of soil per each large garden plant, like eggplants, tomatoes, pepper plants, and some varietals of squash like winter squashes or zucchini. 2 to 3 gallons of soil are generally enough for cucumbers, melons, and similar plants. Beans and peas need about 1 gallon each, and greens can happily grow in any size container.

Smaller pepper and tomato varietals can go in smaller containers, but make sure you’re buying a dwarf variety and that you read the seed packaging or nursery tag carefully.

Carrots and root veggies are a bit trickier. Three to five potato “eyes” will yield a good crop of small potatoes in our potato bags. Beets require more root space and are less tolerant of crowding, so 1-3 plants per five gallons is best. Carrots need to be thinned to least 3”/8cm apart in a relatively deep container, and should be harvested when they reach the desired size to avoid crowding.


3) Squirrels love my veggies! Is there a way to keep them away from my plants?

There are many possible approaches to working with squirrels and other wildlife in your garden. To keep them away from your veggies, we recommend starting with well-secured garden netting as a barrier between your plants and your four-legged neighbors.

4) Do I need to cut holes in my grow bags for water to drain out?

Unlike conventional hard-sided containers, our grow bags are self draining due to the special weave of the fabric used to make them. This material lets excess water drain through the sides and bottom of the bag, so there is no need to cut additional drainage holes—in fact, doing so may shorten the life of your grow bag.

We do recommend placing your grow bags on surfaces that drain well. If your bag is sitting in a puddle or pool of water, it won’t be able to self-drain efficiently.


5) I have good organic potting soil for my grow bags—do I need to mix it with anything?

Generally speaking, no, you don’t need to mix it with anything. For most container plants, an appropriate organic container mix should be fine on its own at first. With use, however, nutrition in the soil will decrease and you’ll need to add fertilizer or compost to add them back and to help loosen the soil. This generally isn’t a problem with new potting soil until it has seen some use, so pay attention to your plants and let them tell you want they need. We generally add light compost or fertilizer to potting soil when transplanting new plants into that container. Again, you’ll need to choose the right.

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