Last week I talked about container gardening. This week let's focus specifically on one type of container - the grow bag.
These fabric containers come in a wide variety of sizes and can fit just about any space - from counter top to backyard. But why use them and how to avoid the potential mess that comes with using a fabric bag?
Tip 1: Soil
This is a very common theme. You need to have the right soil. It is the foundation of your garden and not just any old dirt will do. Healthy soil has all the goodness of everything that has been breaking down and decomposing since forever and is full of nutrients and minerals. Most container gardens, which is what your fabric grow bag is, do well with a mix of ⅓ compost, ⅓ vermiculite, and ⅓ peat moss or coconut coir. For more experienced growers or diy-types, who have a bit more patience, you can make your own compost. I don't have the patience to make my own, so I usual opt for purchasing bags of soil formulated for container gardening or purchase what I need to mix my own.
Purchase or mix enough soil to fill your grow bags. Not having enough soil is almost like cutting your plant off at the knees. There needs to be space for the plant roots to grow out and down. Also, if you are growing plants that require support (think tomatoes), you need that soil to help support the grow cages.
Tip 2: Drainage
Great news! Grow bags, because they are made of fabric, have amazing drainage and allow for fabulous air circulation. Both are necessary to avoid waterlogged soil that will lead to disease or rot in your plants.
Bad news: because grow bags are made of fabric, they have amazing drainage. Plan ahead. If you are planning to put your grow bags in the house or somewhere that water on the floor is not idea, plan to place something under them to collect the water. Plastic plant saucers for smaller bags or, if you have multiple bags or larger bags, a washing machine pan are options.
Tip 3: Watering
While grow bags allow your plants to breathe, the added circulation also increases water evaporation. Grow bags literally allow all sides of your plant to be exposed to air and this leads to the soil drying out faster and the need to water more frequently. Depending on the time of year, the type of soil, and the material that your grow bags is made out of, you may have to water 1-2 times a day.
Warning: Check your plants before you water. As mentioned in previous posts, all plants have their own unique personalities and needs. And the watering requirements of my plants may not match that of your plants, even if they are the exact same plant. Example: I currently have 8 tomato plants in grow bags on a slab of concrete in my back yard. They get full sun all day and I've broken the rule of filling my bags to the top. My plants might get soaked daily in the early morning or late evening if we have temps in the 90s or higher. Otherwise, I will let them go for a couple days between watering. Is this the best practice? Maybe not. But it seems to be working for my plants. Gardening/plant care is not an exact science.
Fun Fact: Growing plants in containers can cause them to become rootbound, the roots grow in a tight, circular manner that eventually chokes the plant. However, because grow bags tend to dry out faster and have been circulation, when roots reach the fabric side of the container, the plant redirects the energy from extending the longer roots and instead sprouts smaller tips that allow for better water and nutrient absorption. This ultimately helps to grow a healthier plant.
Another Fun Fact: Because roots are tenacious buggers, I've actually had plants push roots into the soil below them when the grow bags are placed in the garden.
Tip 4: Fertilizing
Grow bags require more watering, which flushes nutrients from the soil, which means those nutrients need to be replaced more frequently. Solution: more frequent fertilizing. You may need to feed your plants every 2 weeks instead of the typical once a month. Be sure to select a fertilizer that meets your plant needs. Veggies like more phosphorus and lower nitrogen, while flowering plants and foliage plants prefer higher nitrogen.
Tip 5: Size Matters
As with any container gardening, be sure the size of the mature plant will fit into the grow bag you select. This will reduce root shock caused by transplanting.
Top-heavy plants (i.e tomatoes) and root veggies (i.e. potatoes) will require containers that are wider and deeper. Typically these types of plants will do well in containers that hold at least 10 gallons of soil, but this also means that your container can get pretty heavy. Grow bags can offer a lightweight solution when dealing such big containers. Planting dwarf or compact versions of plants can also help with reducing the overall weight of your container.
Plants that require smaller grow bags and less soil include lettuce, kale, bell peppers, herbs, etc. Other edible garden options that are more middle ground in terms of grow bag size and soil requirements, include strawberries and carrots.
What is root shock? Plants don't love sudden change and a few things can cause the plant to essentially go into shock in response. Some changes that can cause root shock include, but are not limited to, light, temperature, container, watering, and disease. If you must make changes to your plant's environment, it is a good idea to do so slowly when possible and allow your plant to acclimate.
Tip 6: Sun Exposure
I've said it before, but I will say it again - make sure you check the light requirements of the plants you opt to grow. However, since gardening is an ongoing experiment, you may find the need to adjust the amount of light your plants are exposed to. Not a problem with grow bags. Because they are generally lighter and some even come with handles, it is much easier to move your plants to meet their needs. Just remember the drainage component to avoid damaging flooring.
Same goes for temperature. If you have placed your grow bags in a location that doesn't offer an ideal temperature range, go ahead an move them. Problem solved.
Tip 7: Transferring Plants
Grow bags aren't necessarily the prettiest containers in the world. However, as discussed above, they are versatile. If you have a decorative container that you want to use, go ahead and place the grow bag with your established plant inside of it. Keep in mind, though, that your decorative container will most likely not have the same level of drainage or air flow so you will need to adjust your watering and fertilization accordingly.
Another perk of grow bags is the option of placing your plant, grow bag and all, directly into the ground once the threat of freezing has passed. This allows plants to be started indoors much earlier and also reduces root shock. If this is something you are looking to do, be sure to purchase grow bags that are biodegradable and intended to be planted in-ground. Another perk is that you don't have to worry about size and soil needs of the mature plant since it will have a ton of room once planted outside.
Tip 8: Storage
Because they are made of fabric, grow bags can be washed and stored when not in use. The plant trays can be stacked, the washer pan slid between cabinets or pushed flat against a wall, and the grow bags folded and placed in a storage cabinet or box.
Or, if you are like me and a bit lazier, any grow bags that are used outside are left there over the winter. Of the 12-15 grow bags I used last year and left outside over the winter, only 2-3 had to be replaced because a falling branch or stick tore a hole in the fabric that was too big to fix. All I did to reuse them this year was empty out the old soil and dead plants, move them to the location I wanted them, and fill with fresh soil. Done. Maybe not the best option, but it worked for me.