I’ve already talked about growing herbs indoors to beat the winter blues, but I know a lot of gardens in urban landscapes are looking to maximize growing space using containers (no, not that kind of pot!) to garden outside too. Whether you’re planting a few herbs in a sunny windowsill inside or growing a large container garden in your yard, a few tips will help make things easier.
First, selecting your vegetables is key. Not only do you need the right types of vegetables, but the right varieties. Some tomatoes, such as Yellow Pear, Super Sweet 100, or Roma, will grow great in pots. Others need more soil and more room than most pots afford. So look for the words “compact,” “dwarf,” or something about containers when choosing your vegetable varieties. But don’t limit yourself to small vegetables and the odd tomato. You can successfully grow anything from potatoes to watermelons to zucchini in a pot if you have enough space to let them ramble. A friend asked me specifically about growing potatoes in containers, and although I haven’t tried this, I did a little asking around and have heard that the potato condo is the way to go! I may try one of these myself in my garden this year, but I don’t see why you couldn’t put a bottom on the condo, fill it with a little extra dirt, and then follow the same design as the in-ground version!
I tend to grow a lot of heirlooms in my pots, just like I do in my raised beds, so if you’re a beginner or someone who prefers hybrids for disease resistance and ease of care, check out this article on good hybrid varieties for containers. Most of the varieties I specifically mention in this post will be heirlooms.
Second, appropriate spacing is important. When your planting up your pots in May with tiny little seedlings, it’s tempting to throw a second tomato in the pot, or plant a pretty ring of flowers around a larger veggie plant. Resist the urge! This past year, I planted a ring of herbs & hot peppers around the outside of a half barrel with one single Yellow Pear tomato in it and had to transplant the poor light-starved peppers & herbs when the Yellow Pear reached five feet tall and three feet wide (and that width is after staking and pruning!). You have to consider spacing below-ground too. Healthy roots are key to healthy, prolific veggies, so make sure you’re using large enough containers for the vegetables you have selected. Garlic, onions, most annual flowers, herbs, and lettuces can survive in smaller, shallower pots, but to do a zucchini, pepper, tomato, or potato, you’re going to need a large, deep pot. Take a look at Arizona Cooperative Extension’s article on container gardening for a list of veggies and the size pot they require.
Water & fertilization are also important because container gardens have less nutrient & moisture reserves available to them because of the limited container size. In an arid climate like we have here in Colorado, expect to water you pots every single day. Drought stress for even one day can cause your tomato plant to drop its blossoms or fruit, and can kill an herb or lettuce plant. If you think you might miss even one day of watering, a battery-powered timer that connects directly to your hose bibb and some drip tubing can be installed for as little as $50 and will be worth the peace of mind when you’re away for the day.
The more you water, the more you need to fertilize because watering can flush nutrients out. I recommend a seaweed or fish-based fertilizer but beware if you have pets (or pests, actually) because some fish fertilizers attract them, and they will dig up your seedlings to get at them. Best to experiment with a little fertilizer in a pot filled with dirt for a day or two–if your dog leaves it alone, you’re set. If not, look for a different product, because you’ll need to fertilize about once a month during the growing season.
My final tip is not to forget aesthetics. Container gardens are likely to be closer to your outdoor living space than any other plants, so make them beautiful. While I have a
rather depraved obsession with love of tomatoes, they really look nicer with a few flowers, flowering herbs, or contrasting vegetation around them. Try edible flowers such as Lemon Gem Marigolds, violas, calendula, or nasturtiums, multi-colored leafy greens like tatsoi, mustard greens, or red-leafed lettuce, or even beans with unusual colored blooms to add a little splash of beauty to your productive (vegetable) pot garden.