A little while back I posted about creating our DIY self-watering seed trays for our seedlings this year. I’m happy to report that all of our seedlings are doing great and are well on their way to becoming thriving grown-up plants (despite getting late-season snow at the end of May).
As I explained in my very first post, our family recently moved from Louisiana to Montana, so we are currently renting a house while we get settled. While we couldn’t dig up the yard to create a full in-ground garden, we didn’t let that stop us from getting our garden going! Instead, we put together a large container garden. Currently, we have a variety of lettuces, peas, herbs, cauliflower, zucchini, bush squash, kohlrabi, tomatoes, hops, and sunflowers all growing and doing well. I’m determined to fill my pantry and freezer with as much home-grown produce as I possibly can this year. With big enough pots and enough TLC, I’m sure we will see our container garden through a productive summer.
If you’re interested in creating your own low-waste container vegetable garden with minimal space and upkeep, read on! Even if you have a large yard or plot of land, you may still want to consider a container garden, because they offer the potential to grow more food per square foot, they are easier to protect from the elements (you can bring them inside if you experience a late frost, hurricane winds, or any other unexpected hazards), and you can still grow food even if the soil quality on your property is poor.
Today will cover five essential steps for a thriving container vegetable garden:
Seed starting
Selecting Containers
Potting Soil
Transplanting Seeds
Ongoing Care
Seed Starting
I cover seed starting and give instructions for making seed starting trays in this post, so I won’t fully go into depth here. However, as a general rule, you’ll want to start your seeds inside about 4 weeks before the last frost and choose seeds that are both well suited to your growing environment and to growing in containers. Tomatoes, lettuces, kale, cauliflower, peas, cucumbers, potatoes, peppers, radishes, eggplants, zucchini and “bush” varieties of winter squash all do well in containers. (“Bush” varieties are more compact than their traditional counterparts). There are some seeds, such as carrots and peas, that don’t necessarily need to be started indoors. Most seed packets have specific planting guides for exactly when and where to start seeds printed on the back, or you can use this handy seed starting guide from the Farmer’s Almanac.
When selecting your seeds you’ll also want to consider the bigger picture: Will you only have one type of plant per container or will you be planting different species alongside each other? If you’re co-planting (I have no idea if that is actually a word), then you’ll want to be sure that any plants you put together have the same needs in terms of sun, soil, and water. Tomatoes and basil are classic planting companions. Carrots and tomatoes do surprisingly well together, as do lettuces and peas. While it is not container gardening specific, The Farmer’s Almanac also has this handy companion planting guide.
Containers & Location
While you’re waiting for your seedlings to grow up and get ready to move outside, you can start assembling the containers that will hold them and the location (or locations) you will place those containers. A sunny balcony, a patio, or a greenhouse on the lawn if you have the space are all good locations, but honestly, you can place your containers in any location that has sufficient sun for your plants to grow. We got a fairly large but inexpensive tent-style greenhouse because we knew we wouldn’t be building a permanent greenhouse at our rental, but we also wanted to give our plants some extra protection from the harsh Montana weather. While the material itself is made of plastic, we felt the investment was worth it because we will be able to use it for many years and we can eventually repurpose the material for something else. A greenhouse absolutely is not necessary for a container garden, but if you want one, there are great options both to purchase one or to build one yourself.
Once you choose your location, you’ll want to assemble your pots or containers. With container gardens, get the biggest container you can fit in your location. No matter what the plant type is, it will do better with more soil (i.e. more nutrients) and more room for the roots to grow. Plus, you can fit more plants in bigger pots, which maximizes your growing space.
Your growing space and soil is calculated by volume, so a pot that is just a few inches wider or taller will not take up much more room, but the actual cubic inches of growing space becomes much larger. For example, let’s say you have a square container that is 10 inches tall, 8 inches wide, and 10 inches tall. Your growing volume would be 800 cubic inches. Let’s make that same pot 10 in x 10 in x 10 in. Just by increasing the width by 2 inches, you get a total of 1000 inches cubic inches of growing space. You won’t miss two inches of space on your patio, but your plants will be much happier!
Plants like lettuces, kale, chard, cauliflower, and herbs, can do well in relatively small pots (1-2 gallons is fine). Tomatoes and papers will want larger pots than this and squash will want bigger yet. However remember, it’s easy to go too small but it’s pretty hard to go too big, especially if you’re putting more than one plant per pot. Root vegetables like carrots and beets will do better in taller containers that give more room for their roots to spread downward.
Buying giant clay and stone pots can be expensive, but you can use just about any container if you set it up correctly. Remember 2 seconds ago when I said leafy greens do well in 1-gallon pots? You can easily repurpose some 1-gallon milk jugs for the task. You probably know someone who has some even if you’ve eliminated them from your household. Pretty much any container that can hold moisture but also has drainage at the bottom (or has the ability for you to create holes for drainage) will work. If you do not have enough repurposed containers on hand, or if you’re not comfortable growing your food in plastic, there are less expensive options out there. I needed more lots large containers so purchased these fabric pots (also known as grow bags) because they are light (i.e. require less energy to transport), inexpensive for the amount of growing space they offer, and sturdy enough to last several years. When we move into our “forever” home, I will be able to easily move them without worrying about anything breaking (or breaking my back trying to lift huge clay pots full of heavy dirt).
So far I’ve been really pleased with them: they manage the planting paradox of holding in moisture while also promoting good drainage quite well. I bought them in the 7-gallon, and 10-gallon, and 15-gallon sizes. For my 10-gallon pots, I purchased this variety because they were taller, and would give more space for any root vegetables. To my pleasant surprise, this particular brand also came without plastic packaging! I’m not 100% if this is true of all their products, but hopefully, it is.
To encourage drainage, you may want to place a layer of gravel or small rocks in the bottom of your pots, especially if you live in a humid environment.
Soil
You can have the best pots with the best drainage and the most expensive greenhouse in the world, and it won’t do you any good if your soil isn’t any good. You’ll want potting soil that is full of nutrients and retains moisture well. Remember, your potted plants only have the nutrients available to them in the pot--they can’t extend their roots down further to get nutrients from the environment like in-ground plants. I highly recommend using organic soil instead of soils with synthetic components and fertilizers. It’s better for the environment and it’s better for you when you eat the fruits (and vegetables) of your labors.
Soils that incorporate worm castings and compost are good choices. Some garden mixes also use coconut coir or peat moss. There are some concerns over using peat moss, as (like oil) it takes thousands of years to develop, so we are using it up faster than the environment can replenish, and also peat moss holds a large portion of the world’s carbon, so using it releases that carbon into the atmosphere. I will admit, I still use peat for some elements of my garden, such as my biodegradable seed starting pots, but I am always on the lookout for better alternatives.
So where do you find soil? There are many different types of bagged soils, with Foxfarm Organic being one the best ones you can get. However, bagged soils, of course, involve a lot of plastic. They can also be quite expensive, especially if you’re looking to fill a lot of containers.
If you have a local garden center, investigate whether or not they will sell soil in bulk. I was able to get 1.5 cubic yards of organic potting soil mix from a local plant nursery for only $70 and no plastic was involved. Instead they scooped the dirt directly into the back of a truck for me to unload at home. It was quite the chore to shovel an entire truck bed full of the dirt into the containers, but well worth it for the cost and ability to avoid plastic packaging. The equivalent amount of bagged soil would have cost me over $200. I strongly encourage everyone to see if they have a similar option in their area.
If you do need to buy soil in plastic packaging, don’t beat yourself. With some care and maintenance, you’ll be able to continue using the soil for many years, and a successful garden can offset the waste involved with getting it setup because growing your own food will eliminate a lot of the upstream waste involved in growing and transporting the items you would otherwise get from the grocery store (you can read more about Upstream Waste in this post).
Transplanting Seedlings:
You’ll know your seedlings are ready to go outside once the danger of frost has passed and your plants have established their first set of “true” leaves. For most plants, their first set of baby leaves tend to be small with relatively round edges. Their true leaves will have more texture to them (think of zucchinis and how the edges of their leaves are slightly serrated and for tomatoes, how their leaves have small points on the edges).
A few days before transplanting, set your seedlings outside for a couple of hours at a time in the morning or evening to help them start acclimating to the outdoors. Bring them inside at night and repeat this each day until your seeds are ready to go in their larger containers.
When it is time to transplant your seedlings, one of the most important things to remember is to be careful of their roots. This is why I use biodegradable starter pots or paper egg cartons to plant my seeds because I can just plant the entire pot in the larger container without disturbing the roots or shocking the seedling too much. I do (very gently) loosen the bottom of the peat pot at planting to make it easier for the seedlings to get their roots down into the deeper soil after they’ve been transplanted, but this is not strictly necessary.
Also, while egg cartons do work as a substitute for biodegradable pots, I still do purchase peat pots because they give the seedlings more space to establish their roots while in their starter containers and gives me a little more growing room just in case we get late snow or frost and I need to keep the seedlings inside for an extra week or two.
If you’re not using biodegradable pots, be very careful when removing the seedlings from their container. You may want to use scissors to help cut away the pot if you’re worried you can’t get the plant out without damaging the stem or roots.
I find the early evening is the best time to transplant seedlings so they aren’t getting placed outside in the heat of the day. This can cause them to wither and die if they get too hot before they get accustomed to their new environment.
Ongoing Care:
Watering: You can’t just move your plants to the containers, leave them to their own devices, and then expect gorgeous vegetables to appear like magic. While container gardens need less work than a traditional card (hooray for no weeds!) they still need some upkeep. The most obvious thing is watering. You won’t want to overwater and have water pooling in your pots, but you’ll definitely want to keep your plants hydrated and happy. I always check my plants first thing in the morning and again in the evening. If you can, avoid watering during the heat of the day as most of that water will just evaporate instead of getting used by the plants. Instead, try to give them a drink earlier in the day before it gets too hot, and then water them again in the evening if they need it so they can hydrate overnight. The younger your plants are, the more you will need to water them and watch for signs that they are drying out, as their root system isn’t as established yet.
Feeding: As mentioned before, container plants get all of their nutrients from the soil in their pot, so regular feeding regularly with fertilizer is very important. You can get granular fertilizer that you work into the soil before watering (or mix with water in a watering can) or you can use liquid fertilizer. Either option will work, so it’s really up to personal preference. As always, you’ll want to opt for organic fertilizer, and you’ll want to fertilize your container plants about every two weeks. When selecting store bought fertilizer, you’ll notice they will have three numbers on them, such as 20-20-20 or 10-15-20. These numbers refer to Nitrogen, Phosphorus, and Potassium in that order. I generally opt for a fertilizer formulated specifically for tomatoes and vegetables such as this Happy Frog Organic Fertilizer (5-7-3).
You could also make your own compost tea if you prefer. Compost tea tends to be weaker as a fertilizer, so you may need to apply it more often. Also, because the composition of one compost pile may vary greatly from the next, your ratios of Nitrogen, Phosphorus, and Potassium will not be as predictable as with professionally made fertilizers. This is not to deter you from trying out compost tea, but if your plants suddenly start yellowing or aren’t producing well, it could be due to a need for additional nutrients.
Thinning: I hate thinning plants. I wish I had space for every single seedling to go on to become a beautifully lush plant. Alas, this is not the case. Of course, you do want to plant a couple of extra seeds when you start them because even the best seeds don’t always have a 100% germination rate. As your plants grow and become crowded, make sure to continue thinning them to ensure your plants aren’t fighting for space and nutrients. Remember, you can eat many of the baby plants you thin! Pea shoots are edible, and microgreens are very tasty in salads and on sandwiches when it is time to thin your lettuces and greens. Compost any thinned seedlings that are inedible.
Succession Planting: Certain plants do well with succession planting. That is, once you harvest the original plant (such as a head of lettuce), you furrow more seeds directly in the garden (or in this case, the container) so you continue getting more of the same vegetable throughout the season. I use this technique for lettuce and kohlrabi until the weather gets too hot for them to grow well, and then I do another round of succession planting just before fall.
Even a large container garden is quite manageable and should only require a few minutes of maintenance each day. With the proper care and a little patience, you should have delicious fresh vegetables straight from your backyard or patio. Also, the experience of having a container garden should be enjoyable in and of itself. I love going out to the greenhouse to smell the fresh plants and just relax in the greenery. I will post an update soon when it is time to start harvesting and preserving the fruits of our labor. In the meantime, happy gardening!