Tomatoes: It's All About the Rotation!

Q. Tina in Woodbourne Kentucky writes: "Hey Mike, I have a memory of a show last fall where you gave really logical reasons for not leaving your tomato plants in the same spot for 3 years. But I've been relistening to the podcasts and searching the questions of the week to no avail. Am I confused about this?"

A. Maybe. First, a reminder that the easiest way to resolve most of your questionable issues is to go to the show's official website YOU BET YOUR GARDEN.ORG and click on the link that says "searchable archive of frequently asked questions". You will be magically transported to a page of previous Questions of the Week that Gardens Alive kindly maintains for us. I just went there to check it out and 'tomato rotation' typed into the search box yielded no results.

Then I thought 'keep it simple' and just entered the word 'tomatoes' and up came over a dozen articles, most of them including a warning about the all-important three-year rotation. I will now plunge into the details, otherwise this article will turn into a treatise on how to use a phone book. (Ask your parents or grandparents about phone books. Their response will keep you enthralled for a good twenty seconds.)

Anyway, there are soil-borne wilts' in just about all of our dirt. Verticillium is prominent in cool climes, with fusarium taking over in the South and West. These 'wilts' occur naturally, and nothing can really be done about them. They are pathogens in the soil that attach themselves to the roots of susceptible plants, especially, as we all have sadly learned in our gardening careers, tomatoes.

(But not just tomatoes. The Morton Arboretum in Illinois reports that some trees are also victimized, including maples and magnolias. Luckily they also include a nice long list of naturally resistant trees...)

These pathogens attach themselves to the roots of suspectable plants and essentially plug up the 'pipes' that transport water throughout the plant. Here's how it works with tomatoes:

Year one in soil that has not grown tomatoes previously: Let's designate the area in which you will inter this first tomato "Planting Spot X" (because it sounds so cool!)

The first season in "Spot X" should be problem-free (unless you or the hornworms manage to screw it up.) Or I should say, 'seem' to be problem free. Underground, the pathogens are already getting to know those attractive roots and begin to colonize them. By the end of this first season, you may notice a little yellowing of the lowest leaves of the plant. No problem; but make sure to remove any discolored leaves promptly. It may slow down the progression, and more importantly, makes your neighbors think you're a better gardener than reality might allow. "How come their tomatoes don't have any yellow leaves?"

At the end of season, remove the entire plant, being sure to get all of the roots; trash it all; do not compost it. Now you have to remember where "Spot X' is for the following season! If you're growing indeterminate tomatoes (tall plants that grow all season long and can reach 14 feet or more) I strongly recommend welded wire tomato cages supported by several metal stakes or lengths of rebar. Stake the cage; not the tomato!

You'll find more cagey details in the "Support Your Local Tomatoes" article in our archives, but in brief, you cut six-foot lengths of welded wire fencing (NOT CHICKEN WIRE!!!) in your driveway, form them into cylinders, place one of them over each little baby tomato plant and then secure them with your stakes Yes, they're tiny now, but each adult plant could soon be loaded down with 40 - 50 pounds of fruit by August, so make sure that cage don't blow over in the wind.

Double Bonus: Each cage built to our PRECISE instructionionies is approximately two feet wide; perfect for spacing tall tomato plants. Allow a full foot of open space all around the outskirts of the cages and you will have just enough room for good airflow between the plants for disease prevention.

October: getting frostbite is NOT gardening. Pull up your plants, and 1) Just leave the cages in place. Or 2) Fill the now empty cages with shredded fall leaves so you'll have the world's finest mulch in the Spring.

Season two in Spot X: I say go for it. Empty out the cages and reserve the leaves. Plant this year's tomatoes right on X Marks the Spot, being careful not to nick or otherwise injure the plant. Be a little heavy handed with water (as the plants are now going to be somewhat impaired in their ability to 'drink' it).

Pull discolored leaves promptly! There's going to be a lot more of them this season. Which is good; removing discolored leaves at the base of a crowded plant allows more precious airflow to the base, where all bad things happen. (And your neighbors will be even more jealous.)

Mulch heavily with the shredded leaves you collected and plan your move to a 'new X' next season. Nobody gets away with three years in a row; the plants will be dead by July. So pick a new spot at least three feet away and use heavy duty plant markers to remind you to plant something else in the old spots.