If you already have an urban farm and want to grow more crops in the space you already have, then containers of all types, shapes, and sizes are a fantastic way of achieving that.
I currently have 50% of my urban farm planted in various containers that we will cover in this article. I heavily practice container gardening because my soil here in Phoenix is terrible, and this has allowed me to scale up growing for the market. Plus, just about any vegetable, herb, flower, or salad greens will happily grow in containers.
BENEFITS OF CONTAINER GARDENING ON AN URBAN FARM
One of the best advantages of container gardening is that it allows you to have a thriving garden just about anywhere. You just need to be creative with where to start. For most new and beginning farmers, tackling the planning and execution of a garden can be overwhelming. Growing in containers can help alleviate that pressure.
Top 6 Benefits of Growing in Containers
Great for small spaces, so you can have a container garden with adequate light, no matter how small a footprint.
Elevated container gardens such as raised beds make gardening accessible to people with mobility issues or limited range of motion.
Tailor the soil to suit your growing needs; this is especially helpful if you live in an area with bad soil. For example, blueberries thrive in acidic soil, but if your garden doesn’t have that, you can still grow berries in a container with the correct potting mix.
It’s a relatively inexpensive way to start a garden. Containers such as grow bags are available in bundles of five or ten for less than five dollars per bag and are excellent containers for various crops and flowers. You can be creative and even upcycle containers to grow out of.
Most containers can be moved to more favorable areas in your yard based on the season, giving plants the optimum growing conditions.
It is easy to break down and move, which is excellent at the end of your growing season.
CHOOSING YOUR CONTAINER
Anything that can hold compost or potting mix can be used to grow plants. However, the caveat is that some planters are more suitable than others for a successful container garden.
Regardless of the container used, ensure there is adequate drainage at the bottom. There are many types of containers to choose from, and below are the top six planters to consider:
Grow Bags – these are my favorite and have become immensely popular because of the wide variety of crops that can be successfully grown in bags. When you choose the right size of grow bag and the right soil, the options are almost endless.
Grow bags can range in size from a few gallons up to 200 gallons. Therefore, regardless of your need, there is a grow bag size that will work for you. Larger grow bags can even be suitable for growing fruit trees.
Grow bags also have the benefit of air pruning because of the porous fabric that these bags are made of; this allows the plants to develop a very healthy root system. If you want to dive deeper into using grow bags, check out this article here.
Raised Beds – raised beds are another excellent option for a container garden. There are many prefabricated raised bed kits on the market that vary widely in price, so there should be something available that suits your budget. However, you can be creative and build your own. This can be done by recycling scraps of wood or old pallets. This is a very budget-friendly DIY option if you are up to putting in the sweat equity.
Permanent Beds - These are similar to raised beds but it is done inground. I use about three of this style of beds on my farm. I accomplished this by using some leftover cinder blocks and scrap wood to frame out my growing area and filled that up with compost.
It's basically a no-till method to set up a grow bed, and it's fast and inexpensive. It saves time and material of builing a standard raised bed. The best nasturtiums I have ever grown have been on one of my permanent beds.
Terracotta pots – these clay pots are very aesthetically pleasing and make great planters because their porous properties allow for proper drainage and prevent overwatering of plants. That porous characteristic allows for oxygen exchange that helps support a healthy root system.
Herbs such as rosemary, thyme, and oregano grow great in these pots. However, the one disadvantage is that these pots become very heavy when filled with wet soil, making them less mobile than other options.
Plastic pots - are another great option, as they are readily available in all shapes, colors, and sizes, making it easy to find something that fits your needs. You can purchase pots from your local improvement store or recycle old containers you already own.
With plastic pots, the cost barrier to entry for small gardens is eliminated because the options are so readily available. If you decide to recycle or repurpose plastic planters, ensure they are of food-grade quality to avoid chemicals leaching into your crops, which can eventually get into your body.
Vertical Planters – If you are extremely short on space, a final option to consider is vertical farming. Similarly to the options already discussed, you can purchase prefabricated versions, or you can build your own with some planning and creativity. I currently use a couple of vertical planters to grow rainbow chard, which has been a game changer. Just be sure to choose a sturdy frame that can support the planter, crops, and watering.
FILLING YOUR CONTAINERS
Now that you have chosen your container, it’s time to fill them up. This is probably the most expensive part of planting this type of garden since good quality potting soil can be pricey, and you will need a lot of it.
However, the advantage of growing in containers is that you can easily tailor the soil for what plants will be grown in that container. Depending on how large your container garden will be, purchasing the soil in bulk and adding amendments as needed would be best. Most major cities will have local businesses that make and sell compost and will likely deliver bulk quantities.
I have purchased my compost from a local worm farm for many years. If you have the space, you can supplement your soil supply by having a compost pile throughout the year to add to your container garden.
What I typically do when filling my large raised beds is to fill them halfway with logs, branches, and other yard waste. When I was short on logs, I simply purchased cheap firewood to fill my beds. Be sure to water in after each layer so the material can settle, then fill the final 8 to 12 inches with high-quality soil. Shallow-rooted crops won’t need more than 12 inches of good soil to thrive.
This technique is called Huegelkultur; over time, all the organic matter at the bottom of the beds will break down and build your soil. You will need to add compost and mulch every season as the material breaks down and settles to keep the soil level even.
Feeding your container plants
Another consideration when planting in containers is adding fertilizer boost throughout the growing cycle. The well-draining advantage of the containers also leeches nutrients from the soil. Depending on your preference, this can be done in many ways; good quality compost and granulated fertilizer are slow-release options. Liquid fertilizers, compost tea, or worm tea are all quick treatment options that make a great addition to give your plants a boost during flowering and fruiting.
There are so many crops that can be grown in containers that it can be overwhelming, but ultimately, you will need to narrow down what to grow based on the size of the containers, variety, and season.
Root crops such as potatoes and carrots do well in deep containers. Match the container to the correct plant. For example, a 7-gallon grow bag will be excellent for large, heavy-feeding crops like tomatoes. A small shallow container will be more suited for quickly maturing crops such as lettuces and green onions.
Here are my top eight plants to grow in a container garden:
Tomatoes – pick a pot that is large enough for this plant. Typically, one tomato per planter works best. Be sure to water and fertilize well since tomatoes are heavy feeders. Provide support such as a tomato cage early on for the best results. I highly recommend growing cherry tomatoes for an urban farm because they are high-value, high-yield varieties that will do great in a container farm setting.
Peppers – like tomatoes, one plant per pot is excellent for peppers, as they are heavy feeders too. Make to have well-draining water with a balanced fertilizer and provide support.
Salad Turnips are great in container gardens when given the right conditions. I would recommend starting with a 10-gallon grow bag with standard potting mix and amending it with a well-balanced fertilizer. They are quick growing and can be ready to harvest on average in 38 days. The Hakurei variety is a good option as they have a milder, sweeter taste.
Lettuce/Leafy vegetables - Leafy vegetables do well in containers. Their shallow root system allows them to be grown in containers of any size. I would recommend growing those in a permanent raised bed or large grow bags and planning on succession planting to have crops available throughout the season.
Carrots – pick a container tall enough to support the long tap root of your carrot, or consider growing short varieties better suited for container growing. Any container at least 12 inches tall will work for most carrot varieties. Carrots are also very sensitive to hitting things in the soil when growing, so be sure to sift your soil so it is free of large twigs or bark.
Green Onions – also called bunching onions, make great container plants because they are quick growing and can be planted at high density. I typically plant about three to five per hole. Keep them well-watered, and ensure they get plenty of sunlight between 4 and 6 hours. They do best with phosphorus-rich fertilizers. Growing them from seed will allow you to choose from a wider variety. I like having some red bulb varieties as the pop of color really helps attract customers.
Herbs – most herbs will do well in a container garden. An advantage to growing some varieties, like mint, that are prolific in the garden is that they will only grow to the size of the container they are planted in. This will prevent them from taking over your garden. Growing your container herb garden close to your kitchen is also a good idea for easy cooking access.
Edible Flowers - are very popular with chefs and are an extremely high-value crop. I grow all my edible flowers in raised bed plants and harvest weekly for my restaurant customers. I even add them to some of my microgreen mixes for a pop color, and it's been very well received at the farmers' market.
To increase your margins, consider starting your own seedlings rather than purchasing from a local nursery. Consider using soil-blocking techniques to start your flowers. Many flower seeds are quite small and do well with this style of planting.
WATERING YOUR CONTAINER GARDEN
One of the challenges of container farming is maintaining proper water supply. Containers are limited in the amount of soil and thus limited in the amount of water available to your plants. Underwatering is as much of a problem for plants as overwatering. Consistency with watering is very beneficial to crops like tomatoes, which are sensitive to fluctuations in moisture.
The best way to achieve automated watering is through drip irrigation. I use a drip irrigation system on my farm with a battery-operated timer. If you are growing on a scale for a farmers market, having an automatic watering system will be a huge time saver. Drip irrigation is better than blasting your crops with a garden hose, as most of that water would just run off and cause more leaching of nutrients from the soil.
Sub-irrigation is another method to solve your watering problems in container farming. This works best with plastic containers. This is a highly effective technique, and it is basically where you create a reservoir of water underneath the soil that is wicked up by the plants as needed.
This method ensures that the soil is always moist, and you don’t need to water as often.
Container gardening is an excellent way to scale up your growing operation. There are so many options to choose from to suit your needs and budget. Growing in containers can allow you to take advantage of unique growing spaces like a front yard.
I currently use a combination of all the containers discussed in this article and will add more in the next growing season. Some of my best-yielding crops have been done using containers. You, too, can accomplish the same with suitable containers, location, and growing medium.