I have put this off as I am reticent to recommend any sort of container gardening shenanigans for anybody anywhere, but as every urban dweller desiring self sufficiency insists on giving containers a go, I suppose I will offer what little help there is to give on the matter.
First, an admission: I was once an avid container gardener myself. My driveway was covered from end to end with plastic pots containing all manner of edible content in varying states of chaos and disarray. My knowledge of the technique is based on personal experience and external reference. My ill will towards the technique is based on the same.
There are three main things to consider when starting your container garden: containers, soil, and water. There are also these other slightly less important things: nutrition, sunlight, viable plants. There are likely several other matters that rest on a tertiary plane of importance, a plane that we may or may not find ourselves exploring together here in the ever-expanding blogosphere.
If there is anywhere you are allowed to skimp when it comes to container gardening, it is in the method’s namesake, the container itself. This can easily become the most expensive aspect of your container garden if you are hellbent on the aesthetic pleasures of plant framing and quality pottery. Pots are not cheap. Plastic containers however, are extraordinarily cheap - as cheap as free on occasion even. I speak of the black plastic containers one will find at any garden center housing the myriad shrubs and trees on offer. Garden centers will more or less always have a stash of empty containers hiding in some forgotten corner of their property, and though they likely have some unlikely master plan for using these pots for some professional gain or other, they are equally likely to let you take some off of their hands. Do not be afraid to ask. Many garden centers won’t part with these pots for free, but will willingly give them up for cheap. I strongly encourage any budding container gardener to go down this road unless money is truly not an object. Some gardeners object to the use of plastic pots for a couple of reasons.
If you want to know about those reasons come to Southbound Gardens Container Gardening Workshop, which will come to pass someday, somewhere, wherein you can obtain a deeper knowledge of the art and danger of this urban shortcut that I recommend never. Plants need room to grow. All of them. Vegetable crops, by and large, grow their roots shallowly, but outward fairly extensively. You want to give them every opportunity to suckle at the dearth of the nutritional stomping grounds you provided them with when you decided to imprison them in those containers devoid of friend or mycohrizzal comrade. Regardless of what sort of vegetable you’re growing in any given pot, you want that pot to be at least 8” wide. At least. Really, you should be giving them 10” to 12”, but they will likely be able to make 8” work. Barely. You are not allowed to cheat on this. If you do, then your vegetables will live, but they will barely grow and they will certainly never grow to their fullest capacity. Ever. Shallow pots are alright however as most vegetables don’t grow roots deeper than 4” or so under normal conditions. You may find that the roots extend deeper in your pots as they are searching desperately for adequate water and nutrition.
If you skimp on decent potting soil, you will not have plants that are even remotely happy and healthy. There are DIY workarounds to this, but today’s not the day you’ll find them from me. Ask the rest of the internet, or wait for the workshop that I have already plugged once and will likely plug again before this blog is over.
Finally, you will have to amend your pots with plenty of fresh potting soil or some other amendment fairly regularly, twice a year or so, if you want to keep growing food out of said pots. Facts of life: soil compacts, drains out of the bottom, gets brittle and weak in composure. Everything dies; everything can be born again.
Watering is of course an important part of any gardening, but in the case of container gardening, it is exceptionally important. Even with decent soil and a reasonably sized pot, you are going to have to water your potted crops daily, almost without exception. The soil will dry quickly, no matter what. When plants are in ground, as they get larger their root systems reach farther and deeper out, lessening your need to quench their thirst extensively. When plants are in pots, as they get larger their roots run out of space to grow and so they drink exceptionally fast of whatever they can get. At all phases of their life, you must water your potted plants often. There are DIY workarounds to this as well which are functional to varying degrees, but you are probably aware by now where I recommend you discover what these are.
Not only must you water your plants often, you must water them deeply to encourage root growth and give your babies at least some modicum of a water reserve should you forget to water one fateful day. Each pot should be watered until water begins dripping out of the bottom of the pots.
The bottom of the pots. This is absolutely essential. If your pots have no drainage your plants will drown in misery. And water. You cannot workaround the need to water your plants daily by leaving them eternally submerged in water. If your pots do not drain your roots will wither and die.
Slightly Less Important: Nutrition, Sunlight, Viable Plants.
If you do not buy a soil that has a healthy bit of fertilizer, beneficial bacteria, mycorhizzal fungi and more in it already, you are going to want to fertilize your pots with regularity - every three weeks or so. Given the nature of pots, the nutrients within your soil will be used up or leached out of the pot somewhat quickly, and you’ll want to renew the food supply to your plant as needed. If you bought yourself the good stuff, you’re still going to want to fertilize once or twice over the course of any annual plant’s life, and every month or two in the case of perennial herbs and the like.
One huge benefit to pots is that they are easy to move. You can chase the sun with them, and experiment consistently with varying degrees of shade and sun as the seasons change. This is the shining light container gardening. Do not let it go out. Take advantage of your mobility.
Some plants are a lot easier to grow in containers than others. Greens and herbs are magnificent in relative terms. Cucumbers and other related veggies, despite their huge above ground mass, have pretty small root systems, and you can get a lot of good work out of them in a container. Nightshades (tomatoes, peppers, eggplants, and a lot of other plants you’ve probably never heard of) are much less into pots. They will grow fine, but their yields are not going to be exceptional. If you want to give it a whirl anyway, give your nightshades exceptionally huge pots so they may have a fighting chance. Root vegetables can be done in pots. but tend to get somewhat stunted, even if the depth of your pots seems sufficient to grow your babies to their supposed ideal length.
Ian writes these. Fearlessly.