Terra Cotta vs. Terra Firma

Any day of the week a garden will be healthier and produce better when it's got good ground and ample sunlight; but should either of these be unavailable or severely limited, container gardening can be a great alternative.  There are a few very important differences between growing your garden in the red clay or growing it in red clay pots that need to be understood in order to make your potted garden a great success. 

First of all, whatever soil you begin with in your containers will be all the soil your plants will ever have.  For this reason, use the biggest containers that will be practical for you.  Practicality will be based on what containers might be available to you already or how much money you might be willing to spend on one or more planters.  Consider also if at any point you will have need to move your garden.  If you are planning on moving in July you may not want to start your herb garden in the largest half-barrel you can find! 

You will also want to make sure that your plants have the best soil they can to start out with.  I love using a 1/2 and 1/2 mixture of soil conditioner and compost such as mushroom compost.  This mixture provides appropriate drainage and also a lot of necessary nutrients that will be available throughout the season.  Potting soils, unless some sort of fertilizer is included, are often low in nutrients and instead are simply providing a structural medium for plant roots to grow in.  Potting soils are also often made primarily of peat moss, which tends to cake up and repel water when very dry and then hold onto water for too long once it gets completely wet. 

The second characteristic to be aware of with container gardening is drainage and the need for a more consistent water supply.  Any pot or planter must have holes drilled in the bottom or your garden will fail.  Plant roots require plenty of water, but too much water pooling in the bottom of a pot prevents absorption of valuable oxygen and the plant will die.  There is the potential of working magic in a solid pot by adding a thick layer of gravel at the bottom and then putting your planting soil on top of that, but really it's just so much better to have a well-drained pot.  The limited soil area again comes into play with water needs as the less soil, the less available medium for holding moisture.  Potted plants will require more consistent watering.  During the hottest, driest days of summer in Georgia, it is likely you will have to water smaller planters twice each day. 

Then, the nature of good drainage combined with repeated watering brings up the subject of leaching.  Leaching is the process by which essential nutrients are literally washed out of the soil by rainwater or irrigation.  Whereas it is possible to garden directly in the ground without use of any kind of chemical or organic fertilizers, it is nearly impossible to successfully do so while container gardening.  If you are choosing to garden in containers, unless your soil medium contains fertilizers already, you should have in mind early on what slow-release granular fertilizer(s) or what form of water-soluble fertilizers you'll be using.  Granular fertilizers come in the form of tiny round pellets that you sprinkle on top of your plant's soil.  Make sure that any form of granular fertilizers you use are "slow-release" as otherwise they will be too strong and will "burn" your plants, causing your garden to fail.  Water-soluble forms are crystallized powders that you mix with water and then irrigate your garden with it.  Granular slow-release fertilizers can be applied once, usually not more than twice during the growing season; the recommended use for water-soluble forms is usually once every week or two weeks.  Both forms are available in either chemical/synthetic formulas or in organic/all-natural versions, and both should be used as directed on the labels.  We'll discuss the details of N-P-K and other nitty gritties of fertilizers later, but for now - anything sold for use in vegetable gardening would be a suitable choice. 

Lastly, understand that plants grown in containers are generally more susceptible to the elements than plants grown in the ground.  Tall plants like tomatoes will be less stable and will either need a larger, heavier pot to prevent toppling over on a windy day, or some sort of fence or trellis for support.  Whereas the ground works to insulate plant roots from extremes of heat and cold, potted plants will react to these extremes more readily.  If you've started an early spring garden in containers and a cooler night (like our 41-degrees last night!) might be a great time for moving the pots into the garage or against a south-facing wall of your home to help keep them warm.  Extremely hot weather makes a huge difference in how quickly the roots dry out and the heat alone can cause plants to seek dormancy as quickly as possible.  Again, the larger the pot and the more soil available to the roots, the more insulated the roots will be from these extremes.  Conversely, the larger the pot and the more soil available means the heavier the pot will be and so it will be  much more difficult to move quickly should you desire a warmer or cooler location for your plants.

Some basic guidelines overall - here again, start small.  Well, start small in terms of the number of containers and the overall number of plants, while aiming at the largest containers practical.  Make sure water is very conveniently located to the spot you have in mind for your container garden.  As with traditional gardening, invest in your soil from the beginning - give them the best start as you can't replace the soil without damaging the plant once the roots have started filling out.  Wood, concrete, or clay planters work great; plastic containers work fine but are much less durable and insulate the planting soil less than any other material.  A good rule of thumb when deciding the number of plants you can grow in containers is similar to square-foot gardening in the ground: you'll need a full square foot of soil area for the bigger plants such as peppers, tomatoes, and cucumbers.  Four smaller plants such as lettuce or herbs can probably fit into the same area, and the like of carrots and radishes can be grown 6 or maybe even 9 to the same square foot.