Usually the calls that come in at the extension office have a common theme. The pattern this month is not about any particular pest or weather phenomenon. This month it seems to be about balance – balance in energy, in minerals, in water, in addressing the weakest links first.
A month ago, I was bemoaning the lack of rainfall. Now some rain has returned, but a lot of it saw fit to park itself over my house in Keller and dumped several inches of rain very quickly, wasting itself on a back yard that does not produce a penny of farm produce tax for the county.
It’s not so important how much rain falls during the year, it’s more about getting critical minimums at the right times. Sweet corn has to have adequate moisture at silking or there just won’t be a crop.
If you are growing tomatoes in pots, regular water and regular fertilizer applications are needed to keep the plants producing. An added dose of fertilizer right before the tomato plants start to make gives them the resources to meet the mineral demands of fruiting.
One of the drawbacks of telling folks to fertilize their plants is they sometimes don’t know when to turn it off. “If a little is good, then twice as much is twice as good!” Ouch.
There are several yards in my subdivision with centipede lawns so lush and green a Kentucky thoroughbred would jump a three-rail fence to get to it. Next year, when the lawns don’t come out in the spring, I am sure the problem will be that the grass is bad, or it was a fungus disease, or grubs.
It cannot possibly be that the homeowner put on way too much fertilizer way too early. It’s a balance in timing and amount.
In the recent heat wave, I got several calls about tomatoes plants ceasing to fruit. It turns out tomatoes need balance, too – especially when it comes to heat.
Now folks, there is a reason – actually a couple reasons – why you do not see commercial tomato production in south Georgia. It’s too darned hot. The reason we put such a premium on getting plants started early is to get production done before the heat of summer hits. If you want to plant an indeterminate variety, one that yields continuously, it is critical to plant it where it is shielded from summer heat.
So why does the heat have this effect on the plants? Plants have a minimum temperature and minimum light level needed just to have the energy to stay alive. There is also an upper limit of temperature and light in which enzymes denature and chlorophyll degrades. These limits change from plant species to plant species based on cuticle and cell wall thickness, pigmentations and other factors.
Tomatoes stop producing fruit before the upper limits are met because the respiration rate increases with the temperature. Each 17-degree rise in temperature doubles the cost of a biological reaction.
Let’s say a tomato variety burns 10 pounds of sugar to make one pound of tomato fruit at 78 degrees. Now, let’s raise the temperature 17 degrees to 95. Now it will take 20 pounds of sugar to produce one pound of tomatoes. But the production of energy is already optimal at 78 degrees. There is no energy left to produce fruit when the temperature gets so high because it is all eaten up by the needs of respiration.
So it is all about balance. Trying to keep it down the middle of the track. Can you grow tomatoes and other plants on the fringes? Sure! Folks do it all the time. They just are not consistently successful or profitable.
There are as many ways to garden as there are gardeners.
Gardner is the extension agent for Bryan County and can be reached at firstname.lastname@example.org.