Talk to nearly any Panhandle gardener and one of the first things brought up in conversation is the difficulty growing large, beefsteak/slicing tomatoes (Solanum lycopersicum) in their home garden. Large tomatoes are indeed among the more challenging garden vegetables in North Florida, affected by myriad pests, pathogens and abiotic issues. However, giving up growing this garden favorite is unwarranted as success can be had by following a couple of often overlooked, simple steps to ward off potential problems.
Choose Resistant Cultivars – One of the major recent gardening trends is the rise of heirloom veggies, particularly heirloom tomatoes. While many of these varieties certainly are interesting and often possess superior flavor/texture, heirlooms are, as a group, extraordinarily susceptible to disease in our climate. Fortunately for gardeners, there are a number of excellent varieties available with large resistance profiles to many common diseases and a similar taste profile to heirloom favorites! ‘Big Beef’ (pictured), ‘Better Boy’, ‘Celebrity’, and ‘Skyway’ are just a few of the many great cultivars with extensive disease resistance available as transplants at garden centers or as seed from quality online seed vendors.
Start Early – Once, you’ve selected the proper cultivar, the next key is to get them in the ground early! I’m convinced one of the primary reasons folks fail with tomatoes is waiting for “traditional” garden planting dates. For instance, an old tradition in the South is to plant your garden on Good Friday before Easter. However, according to Johnny’s Selected Seeds Southeast Sales Representative Blake Thaxton, tomatoes should be germinated and growing in the garden no later than March 15. Mr. Thaxton notes two primary reasons for this, the most important being pest/disease avoidance. Beefsteak tomato varieties take around 70 days from planting to harvest, so a March 15th planting date yields ripe tomatoes around the third or fourth week of May, when pest/disease pressure is still manageable. Pests and disease occurrence becomes exponentially worse in the Panhandle as May trickles into June and July, therefore it is critical that your fruit begin ripening prior to this onslaught. An important second motivation to plant early is that tomatoes stop setting fruit when nighttime temperatures rise above 75°F. At these temperatures, tomato pollen is rendered sterile and though the plant will continue flowering, no fruit will be set.
Mulch – Another overlooked best management practice in backyard veggie gardening is mulching! Those of us who tend flower beds already know many benefits of mulch like soil temperature moderation, weed prevention, and moisture conservation. But for tomato growers, mulch has another benefit – disease prevention! Several serious diseases that affect tomato are soil-borne pathogens (i.e. Early Blight, Late Blight, Bacterial Spot, etc.). These pathogens find their way onto plants either indirectly via water splashing from soil onto leaves or direct contact from leaves and fruit resting on the soil. To prevent these pathogens from infecting plant tissue, apply an organic mulch (preferably wheat straw or tree leaves) under and around plants. This simple step goes a long way toward season-long, yield-saving disease prevention.
Consistent Watering – Everyone knows plants need water but what you might not know is that irrigation consistency makes a huge difference in plant health, particularly tomatoes. Consistent watering is key in helping ward off one of the most frustrating tomato maladies, blossom end rot (BER) – you know, the one where the bottom end of your perfectly good tomato fruit turns to a brownish mush! Though BER is caused by calcium deficiency, the condition is commonly induced by creation of distinct wet and dry periods from non-regular watering, interfering with calcium uptake and availability to the plant. So, while you may have adequate soil calcium, if you don’t water correctly, the condition will happen anyway! It’s also good to keep in mind that mature tomato plants use large quantities of water daily, so during the heat of summer, plants in containers may need to be watered multiple times daily to maintain consistently moist soil. Think about it, you don’t drink 8 glasses of water when you wake up and then never drink again throughout a hot day. A tomato is no different. Allowing your plants to wilt down before providing additional water ruins productivity and can induce BER.
Pruning – I get it. Once you’ve nursed your baby tomato from a wee transplant or seed into a rapidly growing and flowering plant, it seems counter-intuitive to break out the pruners, but to keep your tomato plant as healthy as possible for as long as possible, that is what you must do! Pruning tomatoes should accomplish two things. First, remove the bottom layer of foliage from the plant base, so that water will not readily splash onto the lowest remaining leaves. (I tend to remove all leaves up to the second set of flowers 8-12” from the soil’s surface.) As with mulching, this prevents bacterial and fungal pathogens from spreading easily from the soil surface onto your plant. Second, tomato plants, especially the vigorous indeterminate varieties, often grow more foliage than is necessary for fruit production. This excess foliage can prevent airflow and trap moisture in the canopy of the plant, promoting disease. To open up the canopy and allow for more airflow, I prune off leaves that grow from the primary stems inward to the center of the plant. The idea is to keep the inside of the plant open while allowing enough leaves to power photosynthesis and shade the developing fruit below.
Tomatoes are notoriously hard to grow, but by following a few easy preventative practices, gardeners can greatly increase their chances of realizing harvestable fruit come summer. Please keep in mind that this is not an exhaustive list that will ensure disease-free plants over the entire growing season (you should also get a soil test to make sure your pH and soil fertility are correct and ideally you’d never work in your tomatoes when they are wet, etc., but this is a good place to start!). However, a little bit of planning and prevention early in the season can make growing tomatoes a lot less frustrating! As always, if you have questions regarding tomatoes or any other horticultural topic, please contact your local UF/IFAS Extension Office. Happy gardening!