We’re getting a lot of mail from gardeners who have great-looking tomato plants but no tomatoes. Jim finds the cause.
You’ll hate this column. Good newspapers must be up to date, stories no later than two days old. This writing is three months late.
I’m getting all manner of communications from readers who this season have tried container vegetable growing. They’re confounded with the results.
The plaintive goes like this: “I had so much hope for a great tomato crop. The plants grew like crazy. All my friends have nice tomatoes. Where are mine?”
All plants and no harvest spell over-fertilizing. It happens a lot more now, as fertilizer is appearing in our potting soil. The mistake comes when we add more fertilizer, as we would growing with plain soil.
The plants instantly love the flood of nitrogen. They grow fast and tall, fertilizing our anticipation. Then, when they should be producing veggies, the plants keep adding stems and leaves.
One more application of the Fast-Gro and the soil reaches critical mass. Chemical fertilizer contains a salt base. Too much salt is toxic to plants. It interrupts their uptake of water. This blocks vegetable formation (most are 90 percent water). The plant dies.
Over-fertilization can happen easily enough in open beds. We’re pounded with ads to use more fertilizer and enticed by the claimed results, the pastures of plenty syndrome.
In containers, the problem is magnified. The concentrated salt buildup can be tremendous.
One of my complainers insisted he uses no chemical fertilizer but still has all plants and no tomatoes.
“They should be fantastic — I planted them in pure compost.”
In the plant world, all emphasis is no emphasis. Soil that’s too rich does the same thing. The plants are so busy growing they lose track of their purpose.
I learned this lesson this season. I keep my compost in a pile in my garden over the winter. After spreading it in spring, I figured the spot would be incredibly fertile. I planted a Better Boy tomato there and put up a wooden pyramid to handle the huge crop.
The harvest so far — two golf-ball-size tomatoes, and nothing else showing.
The soil is too rich. The plant is so busy enjoying this luxury, it has forgotten its purpose. Next year, I’ll add at least 50 percent noncomposted soil to the patch.
Don’t give up on your container nonproducers. Scrape off the top layer of soil. It will be salt rich. Then add clean, non-fertilized soil. Water heavily to leach out the chemicals. You might have a shot at tomatoes in October.
Note that if you used a fertilized soil, the chemical will last for up to six months. If you re-use the soil next year, it still may be “hot.”
Another problem I’ve seen is folks who use the new, water-keeping potting soil. It contains crystals that hold water and release it slowly. It often is advertised as solution for container plants outside.
It does work, but it can result in over-watered plants, especially in rains. Plants need chance to dry out. Constant wetness promotes diseases including nasty blights. I’d only use the moisture-control indoors where I can control the water.
I know, this advice is a little tardy. We can only do better next year. Hey, if it were easy it’d be no fun.
Contact Jim Hillibish at firstname.lastname@example.org.