I'm musing on the direction I want to go with part of my urban container garden.
As you can see from last year's photos, I have several large 30-gallon containers up close to the house, on an east-facing concrete wall. I generally put my tomatoes in there, with lettuce, pepper, and basil plants around them.
What I'm pondering is the most effective treatment of the wall, and I'm looking at three options:
1. Leave it as it is, because the bright white reflects the sunlight and maximizes the light that the tomatoes get from all sides, helping to offset the shady hours of the afternoon.
2. Paint it a darker color, to absorb heat and radiate warmth all shady afternoon and long into the evening. Also, the extra warmth would come in handy early in the spring, especially if I use windows to turn the containers into hot beds.
3. The Middle Way: covering the wall with natural reed fencing to do a little of both? Not too hot, not too cold? Also: more attractive.
Paint it red.
Tomatoes do better when they have red light reflected at them.
Red also does a fair job of absorbing heat.
Tomatoes that were gown over red plastic had larger shoots and smaller roots than plants gown over other colored plastic such as white or black. Since the plastic keeps the soil moist and protected, a slightly smaller root would not harm the plant. For tomatoes, using the red colored mulch gave a 20% increase in the first harvest of tomatoes. This is important to farmers because the first fruit of the season can bring in the most money. For all crops, the key is the amount of far-red light that is reflected. In plastic mulch plots, the plant senses an increase of far-red light and will put more energy into the shoot and less into the root. Therefore, if the fruit is produced in the shoot, it will usually be larger.