Despite all of our best efforts, unexpected and extreme weather can throw tomato growers for a loop. To discuss tomato growing advice for challenging weather and every day, along with the best practices to follow to overcome them, my guest this week is Craig LeHoullier, a tomato expert and the co-instructor of my Online Gardening Academy course Growing Epic Tomatoes.
Craig’s been gardening since 1981, and he literally wrote the book on growing tomatoes, “Epic Tomatoes: How to Select and Grow the Best Varieties of All Time.” He also penned the gardening book “Growing Vegetables in Straw Bales,” plus he’s the tomato adviser to the Seed Savers Exchange and a co-leader of the Dwarf Tomato Project.
Last year was Craig’s first growing season at his new home in Hendersonville, North Carolina, and he had an incredible year. 2021 has been dramatically different in a number of ways, which we discussed in depth.
There is still time to join our ongoing Growing Epic Tomatoes course. Find the enrollment page at joegardener.com/GrowingEpicTomatoes. And be sure to download my free Tomato Care Checklist that will help you identify the six main steps you need to take to minimize common tomato issues and have your healthiest tomato plants ever.
Changes Within a Gardener’s Control
The first big difference between Craig’s 2020 garden and his 2021 garden is that he made a decision to reduce the number of plants he is growing. Craig says he is practicing what he preaches by providing more rooms between plants. The space is important because it provides airflow to reduce occurrences of plant diseases. He’s gone from 133 plants last year to 105 this year.
Craig has 20 straw bales with two tomato plants each in his garden, and the majority of those tomato plants are indeterminates. The thing to remember about indeterminate tomato plants is that they will just keep growing and growing until they are killed by frost, so they can take up a lot of room in the garden. And then in front of each straw bale, Craig has a 5-gallon grow bag with a tomato plant
Craig says giving the plants extra space means less improvising on his part to support plants, like how last year he used chairs and sawhorses. His garden had a “random disease fest” by mid-August, he says, and he doesn’t want a repeat of that.
Craig’s attitude had been to let a plant do what it’s going to do once it reaches 4 feet tall. But this year, he is being very attentive to removing suckers from plants so they do not become top-heavy and topple over.
In addition to being diligent about removing suckers, Craig is also topping plants that are growing especially tall. He figures that he will get more fruit from a topped plant than one that he lets sprawl on the ground because he will have fewer disease issues and won’t be sharing fruit with critters.
Changes Outside of a Gardener’s Control
“When you look at a garden, there are things you can do to make them different, and there are things nature can do to make them different,” Craig says.
Sometimes, the weather can overcome our best efforts. In summer, heat, humidity, drought, downpours, and even hail can set our plants back. We can’t control the weather, but we can react and respond appropriately.
As much as we’d like to think we’re in charge, we’re not really in charge. All we can do is practice what we know and try to keep ahead of the challenges that Mother Nature throws at us.
Gardening with Transparency
Craig and I are both very forthcoming about what’s going on in our gardens. Between our websites, social media postings and the Growing Epic Tomatoes course, everything that is happening with our tomatoes is on display — the good, the bad and the ugly. What looks good one day may look not so good the next when diseases, critters or bad weather arrive. When Craig goes on Instagram Live, what his followers see is an accurate representation of what’s really going on.
Craig says he hopes that by using best practices and showing the real results, his followers and students will have their own “aha!” moments that will help them succeed.
I know from your feedback that my followers appreciate that transparency and authenticity — and the imperfection. In the Instagram world, it’s easy to hide behind that perfect picture.
Going the Extra Mile
Craig says this year he’s going the extra mile and finding the energy — even on days when he’s really tired — to tend to his plants for that extra half hour or 45 minutes. When his plants are suckering like crazy or starting to lean, he’ll get his scissors and string, and he’ll put the work in.
“We’ve got a finite fund of energy to put into this,” Craig acknowledged. But, he says, tapping into that energy reserve you have will pay back tenfold. Plants will be less likely to break or tip over because of that extra care we put in.
The plants dictate what his schedule for the day is, Craig says, and his garden is better for it.
Canary in the Coal Mine
To know when his garden is due for a watering, Craig watches certain varieties of tomatoes that are super vigorous, such as Taxi and Martino’s Roma. They are planted in 5-gallon grow bags with just 3 gallons or so of soil, so they are the quickest to suffer from water shortages.
When he waters, Craig counts to 30 at every straw bale and to 10 at every grow bag. That way, he knows his plants are getting consistent water from one to the next, and he doesn’t spend any more time watering than he needs to.
Watering is also a time to be observant. Craig says that’s when he notices that yellow foliage that needs to be removed, the beginning of early blight or the presence of Japanese beetles.
The “Weird Stuff”
In his driveway, Craig grows other crops, and he experiments. That’s where he has hot and sweet peppers and eggplants, and it’s where he works on the Dwarf Tomato Project, a tomato breeding venture for container gardens. Began in 2005, the all-volunteer breeding project has developed more than 70 varieties of compact tomato plants.
Frequent Feeding & Watering
Craig fertilizes his plants frequently, a little at a time. Weekly, he dilutes all-purpose fertilizer at a rate of 1 tablespoon per gallon of water and gives each plant a cup and a half of the solution.
Craig says book knowledge dictates that gardeners should not overwater their tomato plants, but real-world conditions can call for more water. Insufficient and inconsistent water can lead to problems such as blossom end rot, so when it’s been 95 to 100 degrees out, your plants may need you to throw out the rule book and give them more water when they are visibly wilting, Craig says, noting that it is important to reduce the stress on the plants.
Being a Thinking Gardener
Gardeners grow through the accumulation of knowledge and the application of modifications to that knowledge, Craig says. Each growing season, there is a core of activities that gardeners should engage in, but based on that season’s weather, those activities should be modified.
The recent unprecedented heatwave in the Pacific Northwest is an example of the need to adapt to rapidly changing and very challenging conditions.
Temperature & Fruit Set
If your tomato plants are flowering but failing to set fruit, temperature might be the problem. This issue occurs when the temperature exceeds 90 degrees, and it mostly affects heirloom tomato plants that produce large fruit. Craig explains that heirlooms have complex blossoms, in which the stigma is situated in a slightly different place where the anthers don’t always brush against them when the flower is open.
When high heat also brings high humidity, the pollen clumps. Pollination cannot be completed, the flower drops and no fruit is produced. Sometimes, you may find an unpollinated ovary inside that flower that never grows. Instead, it will eventually dry up and fall off.
To encourage fruit set, keep plants well-watered and stress-free. It also helps to take your thumb and finger to flick each blossom. You can also use an electric toothbrush or a VegiBee sonic pollinator to move pollen between the stigma and anther of the flower.
There is a short window when tomato flowers release pollen, Craig says. It’s when the flowers go from pale yellow and partially open to fully open. Craig finds that the pollen comes out best before the flower has come really wide open and started to dry up. Craig adds that there is probably enough pollen in one flower to pollinate every flower in your garden, if you are planning on cross-pollinating plants yourself.
If you do cross-pollinate, the fruit that year will be unaffected. But if you save that seed, next year’s plants will produce unexpected hybrids.
Craig says tomato plants with fruit up to the size of a golf ball will likely not have pollination failure in high heat, but for fruit that is the size of a tennis ball or larger, the issue is common in extremely hot weather.
High temperatures when tomatoes are ripening will also affect the pigments. The fruit color you would normally expect to see may not come because the heat affects the chemistry that determines color.
Best Practices to Prevent Tomato Diseases
Mulching the grounds keeps soil-borne diseases from splashing on the plant foliage. If you do find diseased foliage, remove it ASAP.
One of the reasons Craig uses straw bales is because they are free of tomato diseases that live in soil. If soil borne-diseases are present in a garden bed that you would still like to use for tomatoes, you can put down a barrier and place straw bales or containers on top of the bed. That way, you can benefit from that ideal, sunny location while depriving pathogens in the soil of a host.
As mentioned earlier, it’s also important to space out plants to provide room for airflow. Moving air dries out plant foliage, which is important for disease control. Airborne pathogens may just blow through in dry conditions. However, if plants are wet from morning dew, rain or overhead watering, the fungal spores will cling to the moist foliage. This is how early blight, septoria leaf spot and some other tomato diseases arrive.
Some pathogens are seed-borne, so if the seed coat was infected, that plant is a ticking time bomb, Craig says.
I hope you enjoyed my conversation with Craig LeHoullier. If you haven’t listened yet, you can do so now by scrolling to the top of the page and clicking the Play icon in the green bar under the page title.
How have you had to adapt to tomato growing challenges? Let us know in the comments below.
Links & Resources
Some product links in this guide are affiliate links. See full disclosure below.
joegardener Online Gardening Academy™: Popular courses on gardening fundamentals; managing pests, diseases & weeds; seed starting and more.
joegardener Online Gardening Academy Perfect Soil Recipe Master Class: Learn how to create the perfect soil environment for thriving plants.
joegardener Online Gardening Academy Beginning Gardener Fundamentals: Essential principles to know to create a thriving garden.
joegardener Online Gardening Academy Growing Epic Tomatoes: Tomato expert Craig LeHoullier joins me in leading this course on how to grow healthier, productive tomato plants and how to overcome tomato-growing challenges.
“Epic Tomatoes; How to Select and Grow the Best Varieties of All Time” by Craig LeHoullier
“Growing Vegetables in Straw Bales: Easy Planting, Less Weeding, Early Harvests” by Craig LeHoullier
Disclosure: Some product links in this guide are affiliate links, which means we get a commission if you purchase. However, none of the prices of these resources have been increased to compensate us, and compensation is not an influencing factor on their inclusion here. The selection of all items featured in this post and podcast were based solely on merit and in no way influenced by any affiliate or financial incentive, or contractual relationship. At the time of this writing, Joe Lamp’l has professional relationships with the following companies who may have products included in this post and podcast: Rain Bird, Corona Tools, Milorganite, Soil3, Exmark, Greenhouse Megastore, High Mowing Organic Seeds, Territorial Seed Company, Wild Alaskan Seafood Box and TerraThrive. These companies are either Brand Partners of joegardener.com and/or advertise on our website. However, we receive no additional compensation from the sales or promotion of their product through this guide. The inclusion of any products mentioned within this post is entirely independent and exclusive of any relationship.