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Tomatoes
Crop rotation, spacing, pruning, and irrigation will yield better tomatoes and help prevent parasites.
What is wrong with my tomatoes?
Tomatoes are the beautiful, delicious, iconic garden crop, but with so many things that could be wrong with your tomatoes, it’s a wonderfully, and worryingly, huge question.
Let’s start with some basic tomato maintenance for good plant health and go from there.
Crop rotation: Don’t plant tomatoes where other members of the solanacea family have been planted in the last four years. This includes potatoes, peppers, eggplants and other tomatoes.
Good airflow and good sunlight: Avoid the temptation to cram 20 plants into a 3 by 8 inch raised bed. Wider spacing will give healthier more productive plants and prevent the development, and rampant spread, of disease.
As they grow, many tomato plants want to fall to the ground and sprawl. The plants require staking, or some form of trellis style support. The fruit will be less prone to rotting and the plant will be less susceptible to soil born diseases.
Bottom pruning: Chop off the lower tomato branches, especially the ones that droop into contact with the soil. Prune the bottom 18 inches of the plant to significantly reduce the chances of soil borne diseases taking hold.
Mulching around the base of the tomato plants can help retain moisture (a lack of which can contribute to blossom end rot) as well as prevent soil splashing onto the lower leaves during watering and heavy rain events.
Even with excellent maintenance, the disease and pest pressure on tomatoes can be high.
Contacting your local cooperative extension service is a great resource for identifying and treating plant pathogens, but here is a brief list of some common ailments:
Chunks of tomato missing: Something is eating it! In my garden I’ll either blame the chickens or the tomato hornworms. Look for large green caterpillars with a red spiky horn.
Rotting/brown end of the tomato: Most likely blossom end rot, caused by a lack of available calcium. Either your soil is low in calcium or there is too little water for the plant to absorb the calcium.
Flowers but no fruit: Daytime temperature above 90 degrees or nighttime temperatures below 55 degrees or above 70 degrees, as well as humid conditions, will diminish the effectiveness of tomato pollination and therefore fruit setting.
Dying leaves: This could be any number of bacterial or fungal diseases including early blight, late blight and septoria leaf spot. Identify the disease through your cooperative extension service and treat accordingly.
If you are growing open-pollinated, including heirloom, varieties, I would encourage gardeners to save seeds.
By saving seeds from those plants, you are saving strong genetics to carry forward. If you want to know more, we’ll be answering a question on seed saving in the next edition.
Last year it was so dry that I was watering almost every day, but my garden still seemed to suffer. What can I do differently?
Last year was exceptionally dry, but with climate change realities weather extremes are likely to continue.
If we face another super dry summer, there are some things that you can do to keep your plants from being parched:
Mulching: This is an amazing and low tech solution to water retention. Basically you are covering the soil to prevent water loss through evaporation. There are many mulches that are effective, but I like using weed-less wheat or oat straw because it will also break down and add nutrients to the soil. Other techniques include using a trailing plant to act as a living mulch and shade the soil, this is the role of winter squash in the traditional three sisters of corn, beans and squash.
Deep soaking: You can water every day, but if that water only penetrates the top couple of inches of soil, it is not helping your plants. Watering less often, but really soaking the root area is much more effective. This will encourage greater root development and provide water where it is needed. You can achieve this with a hose, but irrigation systems can save you some effort.
Irrigation systems: There is a perception that irrigation systems are a farm tool only, but in reality you can set up some very cost effective systems on a small scale. The advantages of irrigation are savings in time and effort, plus the ability to regularly provide deep soaking in precise locations. So, if you are serious about growing food, speak to your local garden center about irrigation systems.
Shade: Natural shade, shade cloth or tall shading plants can offer some mitigation to the baking effect of long hot days. Plants with shallower root networks may fair better with some protection from the harsh afternoon sun.
About the author: Chris Smith is the community coordinator for Sow True Seed, an Asheville-based company that specializes in open-pollinated, heirloom, and organic seeds. sowtrueseed.com.