Saturday, September 22, 2012

...and move it all around

Tempus fugit! It's already been more than a year since our first post (Hello there world - August 9, 2011). Wow! Never thought we would still be doing this after a year. But here we are, non the wiser. Well, maybe just a bit wiser.

When we started everything was going great, full steam ahead. We were producing lots of tomatoes, peppers, cucumbers, flowersstrawberries, etc. Happy times! All that stopped a few months ago. Plants languished, production went significantly down, growth stalled. Part of it was poor care and maintenance (mea culpa) but that couldn't be the whole problem. Something else must be at work. After some deep thinking (and online research) I think we might have stumbled upon the root of the problem: Soil.

Soil!? But isn't soil one of the advantages of container gardening. Not having to worry about it. So we thought. In sub-tropical climates container gardeners rarely have to worry about soil. They plant at the beginning of the season with fresh soil and at the end of the season when plants die soil is discarded (or even better, used towards the compost bin). Fresh soil is then used when spring comes around. In tropical climates where perennial plants are common soil becomes an issue.

Here's what happens to soil after time passes.

1. Nutrients are depleted - Nutrients are depleted from the soil as plants consume them. Not a real issue with containers since we administer fertilizer on a regular basis (you are administering fertilizer, right?).
2. Soil collapses - Soil tends to collapse and become compacted. Nutrient absorption may be reduced due to this. However, this is usually not a big concern in containers.
3. Pests and diseases - Pests and diseases develop in soil as time goes by. These organisms may become dormant until the right conditions (temperature, host, etc) are present. Diseases typically affect a family of plants rather than a single species. Very important since a few common plants (tomatoes, peppers, potatoes) belong to the same family (Solanaceae).

Pests and diseases are the biggest concern to reusing soil. Soil harbors many types of viruses and bacteria. Healthy, mature plants are barely affected by these organisms. However, young plants are vulnerable (plants behave similar to humans, the young and the old are usually the most prone to disease). Therein lied our problem. We had a few combopots with spices, greens, ornamentals, and fruits. Spices are, with some exceptions, perennials; greens are annuals; ornamentals may be either annuals or perennials. Fruits usually have to be replaced after a season, two at the most, since their production is greatly reduced as time goes on. Since we didn't want to lose our spices and herbs we kept out pots intact, soil and all. Mistake 1. Then we went and compounded our mistake with Mistake 2: Replanting species in the same containers. Right on cue diseases started attacking our young plants with most plants never being able to produce fruits.

If you have monopots the solution is simple: Discard soil at the end of the growing season. But what to do with combopots where soil cannot be completely discarded? There is a simple solution. Crop Rotation. This technique is used by large scale farmers around the world. The idea is to move crops around and not grow plants from the same family in consecutive seasons. So if you planted tomatoes in one container your next crop could be arugula or lettuce. If you had peppers then you can alternate them with strawberries or onions.
Simple, right? So learn from our mistakes and rotate your crops.