Farmers, gardeners, and scientists have known for some time that tomato (Solanum lycopersicum) is sensitive to heat stress at flowering and fruiting. Pollination and fruit formation can be disrupted when temperatures >90⁰ F. during the day and >70⁰ F. at night. Other fruit problems like yellow shoulders and white internal tissue are also caused in large part by heat stress, especially when determinate (self-topping) varieties are grown and pruned heavily.
If you feel that high temperatures are reducing tomato flowering and fruiting in your garden you can try moving crops to spots receiving late afternoon shade or you can cover plants with 30% shade cloth (a mesh material that blocks about 30% of sunlight). Another option is to try some of the many heat-tolerant tomato varieties. Heat tolerance is a major focus for tomato breeders around the world.
This year, some HGIC staff tried four determinate, hybrid varieties developed by Southern breeders (the first three are from the University of Florida) that I started from seed at home. They all have excellent disease resistance:
Florida 91 (F1) 72 days (transplant to harvest). 9 to 11 oz. red tomatoes
Heatmaster (F1) 75 days (transplant to harvest). 7 to 8 oz. red tomatoes
Jamestown (F1) 80 days (transplant to harvest). 9 to 10 oz. fruit. Purported to have a deep red crimson gene and high lycopene content
Phoenix (F1) 72 days (transplant to harvest). 8 oz. red tomatoes
I took out my tomato plants this week. It’s a lot earlier than I’d normally do it, but I had my reasons (which I will discuss below). Picking the last fruits and chopping down the stems made me think about all the decisions we make as gardeners, and how a lot of the questions we Master Gardeners get are about those choices. We might get asked at this time of year, “Am I supposed to take out my tomato plants now?” Maybe with an undercurrent of “Will I get in trouble with the garden police if I do it? Or don’t do it?” but in any case with uncertainty about doing the right thing. And the disappointing answer we long-experienced garden gurus usually give to questions like that?
Nothing causes that sinking feeling like walking into the garden and seeing one or more tomato plants wilting. Not just some lower leaves that are yellowing, curling, or drying up from leaf spot diseases. No, I’m talking about healthy green leaves and stems that start to go limp. Oftentimes, this spells the beginning of the end for the affected plant(s) so it’s important to figure out what’s causing the wilting symptom. Even if you lose one or more plants this year you’ll want to prevent a recurrence next year. UME’s Home & Garden Information Center seems to be getting more tomato wilt questions this year than usual.
Wilting may indicate that roots or stems are injured, soil moisture has been too high or too low, or that the vascular tissue directly below the epidermis (skin) of tomato stems is blocked up with fungal or bacterial pathogens. Plants with disease-caused wilt should be removed. Here are some possible causes for wilted tomato plants in Maryland.
Fusarium wilt– this disease is caused by a soil-dwelling fungus. Lower leaves turn yellow and leaves and stems begin to wilt, often on one side of the plant. Leaves may revive overnight. Cutting affected stems lengthwise with a razor blade (directly below the surface) will reveal brown discoloration or streaking. The disease rarely infects all of the tomato plants in a row or a bed.
This fungus can survive in the soil for years even if the tomato is not grown in that location. One solution is to grow resistant varieties- look for those that are resistant to at least two of the three known races of fusarium wilt. Example:
I think it is safe to say that it is officially tomato season in Maryland! For people that do not grow their own tomatoes, many visit local farmers markets, roadside stands, or grocery stores to purchase these delicious treats. How are you getting your tomato fix in 2021? Do you have a favorite tomato variety you grow at home?
Soil type and growing conditions such as temperature and amount of available water can influence the taste, sweetness, and texture of a tomato, but there is some background information that can help guide your tomato buying or growing. My family and I grow 10+ different varieties and anywhere between 150-200 tomato plants each year for our small, fresh vegetable business. I want to share some lessons with you that I have learned.
Below are some basic terms to know (for a more detailed explanation of these check out this blog post). I’m going to make some generalizations about the terms when it comes to characteristics that people are looking for in eating qualities:
Variety– there are hundreds of varieties of tomatoes. Each variety has a special characteristic that makes it different from another variety — shape, size, color, taste, etc. Varieties can be open- pollinated, heirloom, or hybrid. These terms relate to how the seeds are produced season after season and are important if you want to save seeds in your garden.
In some situations, especially in greenhouses, growers will utilize bumblebees to ensure that pollination happens; however, cross-pollination is not needed for tomatoes, as they are self-fertile (a complete flower with both male and female parts, so just the motion of the flower opening is usually enough movement for pollination to occur). In nature, wind and rain help tomato pollination to occur. In my high tunnel, we shake our vines every few days.
Open-pollinated plants have been crossed in nature by insects, wind, rain etc., several times and most variability has been lost through natural selection and natural crossing. These often breed “true” to name and characteristics. However, these plants are more likely to produce fruits that have deformities like catfacing.
Heirloom is a special designation of open-pollinated plants that are 50+ years old and often have a fun story that goes along with the name. They may have some variability in size, shape, and color, but are usually pretty standard. Heirlooms/Open-Pollinated varieties are often softer, thinner skinned, get more bruises from handling, and are harder to pick/pull off the vines. My favorite heirloom and story is about the Mortgage Lifter, which was bred in West Virginia by a mechanic that was so successful that he ended up growing plants and selling them to pay for his mortgage in just 6 years.
Hybrid or F1 generation seeds are the result of a specific cross of two parent plants. The hybrids are often bred for a specific outcome such as disease resistance, color, or use. Often these tomatoes are very uniform in shape, size, and color when ripe. Many times hybrid tomatoes are more “sturdy” tomatoes– not as soft and will hold up better on the shelf. Often, the more ripe these tomatoes are, the less thick the skin appears and the sweeter they taste.
In my opinion, if you choose accordingly, every tomato has a perfect use.
For salads, I like a tougher-skinned tomato, so I choose a hybrid. Who wants a tomato that gets all over the other vegetables in the salad? Also, if someone in your family doesn’t like tomatoes, these types are easier to pick out.
Making juice, sauce, salsa, or anything that you want to be thicker– heirlooms, hybrids, or paste tomatoes (sometimes a mixture of all work the best)– any type will work but a longer cooking time may be required to get the correct thickness.
Eating fresh on a sandwich– heirlooms often have the best flavor and texture, but if overly ripe, they tend to be a little mushy. Hybrids will work well, especially if you let them get fully ripe!
Sometimes people use overall shape to categorize tomatoes, but the shape doesn’t always fully describe the tomato.
Beefsteak- is a particular variety name, but many people also use this term to describe a large tomato. Sometimes these varieties have a core that isn’t edible.
Slicing- describes a large tomato often used to cut across and make a nice slice, often important to people that want to eat a fresh tomato sandwich.
Cherry- very small tomato, eating in one bite without cutting.
Pear- small pear-shaped tomato, often eaten whole, much like a cherry.
Grape- similar to a cherry, but usually smaller in size.
Oxheart- tomatoes shaped like a heart that often have a large core that is not usable.
Paste- oval to pear-shaped tomatoes that are meaty with fewer seeds. They tend to have less juice and are preferred for drying, canning, or sauce.
Skin thickness is a very important characteristic!
Hybrids often have tougher or thicker skin, which makes them easier for picking and handling in mass production. If you like to squeeze tomatoes to check for ripeness a thicker skinned variety can be misleading in how tasty or ripe a tomato is.
Knowing the characteristics for each variety can be really helpful in determining ripeness.
For example, we grow several types that are pink when fully ripe. But if we do not mark where these are planted it is easy to leave them on the vine too long and they get overly ripe and then are not marketable. Likewise, if you are shopping for tomatoes and do not realize that there are pink varieties, you could be missing out on a very tasty treat!
Knowledge is power when it comes to choosing the best tomato for your purpose! Please, on behalf of gardeners and fresh vegetable growers everywhere, do not squeeze the tomatoes to test for ripeness! Take a chance and try some different varieties this season and next!
By Ashley Bodkins, Senior Agent Associate and Master Gardener Coordinator, Garrett County, Maryland. See more posts by Ashley.
I had a lot of goals for improving my garden since last year’s adventure which meant new things to build! However, with the current prices of lumber and materials, plus my only basic carpentry skills, I didn’t want to go all out creating beautiful, sturdy, perfect designs and structures from new materials purchased specifically for these builds.
I wanted to quickly build tomato support, floating row cover, a large trellis for climbing plants, deer fence, and a garden gate all without spending too much at the hardware store or spending a ton of time planning. That meant largely using scrap wood I had laying around or cheap materials like PVC, and going for it.
I’m trying tromboncino squash this year which really climbs, and I also wanted to allow cucumbers to climb, so I thought I’d build some sort of large support object. I had a bunch of 2×2, 10 ft long lengths of wood left from contractor work in my basement and thought that would be good material. I wanted something tall that I could walk under and pluck vegetables from. Plus, I wanted it to be non-permanent.
I decided to make this ladder-like structure with a hinge at the top so that I can collapse it and store it in the garage without taking up a lot of space. I bought a metal threaded rod, drilled holes through the wood at the ends that would make the apex of the structure, and ran the rod through those holes to make a hinge. The rest is built with wood screws. Metal eyelets were screwed into the wood so that I could run twine crisscrossed through the structure to allow plants to climb.
The structure was a bit wobbly on its own since it is so tall and not wide, so I worried about it getting blown over during a storm — especially with leafy plants acting as sails. I tied rope to two cinder blocks that pull down and away to give it more stability.
Fence panel tomato hangers
I saw these cool tomato clips online; you can have some sort of structure to hang a string from, then use these clips to fasten joints of the tomato plant to the string to hold it up. With these, all I would have to do for tomato support is to make some sort of triangle or tripod with a high point I could tie string to. It seemed like a simple way to build something. Also, I liked the way my trellis folded flat for storage.
Again, leftover from contractor work, I had some parts of wood fencing from a recently replaced segment of fence I had done. I took off a bunch of the boards, leaving the two outside ones connected by the horizontal segments, and connected two of the removed boards to the others via hinges at the top. I added more horizontal support at the top and bottom, then added eyelets at the top crossbar to tie rope to. This fits right in my 4’x4′ tomato bed. The strings hang down and with the clips, hold up the tomatoes.
Easy PVC piping structures
I went to the hardware store and picked up several lengths of 5 ft white PVC pipe and a handful of T connectors. I didn’t have an exact plan, and I probably should have bought a bit more of everything, but I was able to start with building floating row cover for some of my squash, and then when that wasn’t needed, I reconfigured it into support for my tomatoes.
I cut the pipes: some in a third and 2/3 lengths. Connecting them with the T connectors, bending, and wedging the ends of the pipes into the corners of the raised beds, I was able to make an archway over my 4ft square section of raised bed. For floating row cover on squash, I draped row cover fabric over it and pinned it down with bricks around the edges. For tomato support, I drilled a few holes, screwed eyelet hardware in, attached twine, and used tomato clips to hold up tomatoes.
The 1/2in pipe is a little flimsy, and I ran out of enough pipe to make as much support as I wanted.
I left on vacation for a week and came back to totally collapsed tomatoes. No big surprise there. This design is good for row cover, but not for tomatoes beyond a certain point. I need stronger materials for this one.
After the PVC failure, I wanted a quick way to build something that would hold up the tomatoes. I’m running low on quality materials, so I made this unimpressive support out of two fence panel boards, and the other longest piece of scrap wood I had around. Two wood screws connect them at the top. I don’t think I will keep this for next year as it isn’t collapsible, isn’t that sturdy, and I would hope to make something better if I need something next season. Clips were used again to hold up the plants.
Micro deer fence
I’ve got one 4’x4′ raised bed segment with corn in it that got devastated last year, presumably by deer. Originally this year, I was planning on building a tall deer fence around my entire garden area, similar to this one. I understood that the fence doesn’t need to be particularly strong – just tall enough they couldn’t jump it.
Then I had the idea, “Dan, you clever guy – why don’t you fence ONLY the corn and save a lot of effort!” So I decided to make a tall, twine fence around just the corn.
Again, with leftover fencing boards, I just screwed four of the boards vertically to the walls of the raised beds, tapped some nails in them for string, and wove twine around the whole thing.
It was soon after I finished stringing this thing up that I realized the error in my logic (most readers here were probably yelling at their screens): yeah, a deer cannot jump into my corn field, but they sure could stick their snouts through the gaps in the twine and much fairly unhindered.
I mused about stapling a segment of the rodent fence material used for the outer fence around the four boards, but in the end, laziness and the sense of experimentation helped me decide to leave it as-is and see what happened. Perhaps the deer would be weirded-out enough by the twine to leave it alone.
As of this writing, we are beginning to harvest corn, and it hasn’t been touched which is further than we got last year. Fingers crossed this trend continues.
Building is fun
It’s been fun building. I’ve done this all without breaking out a ruler or tape measure! Mostly, it’s hammer, nails, wood screws, drill, and string that I’m using. Nothing fancy. Luckily, produce does not care if all corners are square, and good enough is generally good enough if you don’t have to support more than a couple plants.
The last item I’ll mention is a little gate panel built from the absolute last pieces of the 2×2 wood. I didn’t even have enough to make a diagonal cross piece that went from corner to corner. I stapled a bit of wire fencing onto it and put a slide bolt to shut it. My wife was tired of having to hop the wire fence to get into the garden, so this was the solution. Again, not strong or beautiful, but it works.
Hello again! Last year, I published a series of blogs chronicling my 2020 growing season from the perspective of a “semi-novice gardener.” Some things went well, some things did not, and I learned a lot in the process, thus I am upgrading my gardener status to “intermediate!”
This year, I will share my work with the class again, but with a focus on certain challenges I encountered last year and what I am doing to do better this time.
For starters, my wife Krysten decided to try seed-starting this year. We set up a grow station on a shelf in the basement with a grow light. I used a smart outlet to power the lights and programmed it to turn on at sunrise and off at sunset. Krysten even pointed a fan at the seedlings, as she read that it simulates a breeze and helps them grow stronger than if they grew without any breeze pushing on them. We started Tomatoes and squash. This was Krysten’s department, so I don’t have a ton of details to share, but we got a ton of tomato, cucumber, and squash seedlings out of it.
We had a cubic yard of compost delivered (along with mulch and soil for other projects) and added that to the previous year’s soil in the raised beds.
Our overall plans and goals
Like last year, we are growing:
Unlike last year, we are attempting strawberries and tromboncino squash. Tromboncinos are purportedly squash vine-borer resistant (a big issue for our squash in the past), easy to grow, and I thought it would be fun to have high-hanging vegetables.
Like last year, we have several pollinator-attracting plants in the garden, but this time, we are keeping them in pots and not planted in the raised beds with the vegetables since we had issues with overcrowding last year. We’ve got cone flowers, milkweed, marigold, lilac, zinnia, and dahlias around the perimeter.
We are upping our security from munching mammals such as deer and rabbits. Pictured at the top of this page, we still have the low rabbit fence as last year, but we are going to build a high fence to keep out deer JUST around the bed with the corn. I thought this would be much easier than creating a high fence around the whole garden area like in this video.
We are taking steps to stop squash vine borers from killing our squash plants mid-season, and that will be detailed in a future blog post.
I’ve built a big support structure for the tromboncino squash; it is the big triangular ladder structure you see in the photo. I am planning on some different structures to support tomatoes as well, and I will detail my construction projects in a future post.
One notable item
Before I sign off, I thought I’d share one interesting issue I discovered with my tomatoes:
I found these weird white growths on the stems of my tomatoes last week. I sent in this picture in to the horticultural consultants at Ask Extension (you can too!) for identification. They answered:
Those are adventitious roots along the stems. See this page on the HGIC website. Some heirloom varieties of tomato tend to produce these roots, which would grow into normal roots if placed in contact with the soil. In some cases, adventitious roots are a reaction to a stressor (too much water/poor drainage, high nitrogen, even exposure to herbicides). There is nothing you need to do other than consider if the plant was under a period of stress and then improve the conditions, if possible. For example, if the plant was growing in a pot with poor drainage, if you move that plant into the ground with good soil conditions, those roots will develop into normal ones to support the plant (assuming the plant is otherwise healthy, no disease issues).
This particular tomato plant is in a pot. It may have been over-watered, and it had also been humid and rainy in the last few days. It’s good to know it isn’t a big deal. We’ll just watch out how much we water that one.
Stay tuned! My next update will likely be about all the construction projects I’m wrapping up as I write this post. I’ve got the big triangle trellis, tomato suspension supports, row cover support, a new garden gate, and deer fencing around one bed.
Yes, I, Bob Nixon, am guilty of the shocking crime of tomatocide.
I didn’t mean to do it—of course. I’m a University of Maryland Master Gardener Emeritus. I should have known better. Yes, I should have.
Why did I do it—age, early-stage forgetfulness, or worse?
No, I’m only 80, the new 60, so age isn’t a factor, and please stop smiling. Forgetfulness? Not really because when I go into the garage to get my weeding hoe or pruning shears, I usually—yes, usually—remember why I’m there.
But I did kill my tomato plants this year—lots of them.
They all started out beautifully, either from seeds I started in cups, or, later, replacements that I bought at the local hardware store and my favorite nursery. Brandywine, Celebrity, Cherokee Purple, Better Boy, Favorita, and Five Star: they looked great when I set them out in my small veggie gardens that wrap around the top of our backyard hillside.
I had carefully prepared the beds, dug planting holes and sprinkled in a bit of fertilizer, carefully placed the plants, watered them, mulched them, and caged them. They started to thrive, to reach for the sun. What joy and contentment for a lifelong tomato grower.
And then I started to worry. Tender young leaves curled under and sometimes twisted. Plants stopped growing.
Herbicide drift? Too much water? Some insect or mite problem? Some strange new tomato virus?
I researched at the Home & Garden Information Center and other online websites and analyzed my situation. Logical conclusion: herbicide drift. But I knew of no neighbor using 2,4-D or other herbicides.
So, I replaced the most severely damaged plants—all of which I had started from seed—with the store-bought ones. And relaxed and watched my new plants grow. And then the replacements started to curl and twist.
Just what is going on, I asked myself? I went online and fired off my question to “Ask an Expert” at the Home & Garden Information Center.
An expert replied: “The downward curling and twisting sounds like phenoxy (growth regulator) herbicide injury…. The injury is often random. A few plants affected in one row. Plants do not recover. 2,4-D drift can be insidious! There’s still a chance that some businesses have tomato plants.” The ellipsis included this link: Herbicide Damage on Vegetables.
I responded: “Thank you… for confirming my worst frustration—probably 2,4-D drift. And I could have added in my question that some early leaves on a nearby row of zucchini were similarly ‘stunted,’ but those plants seem to be putting out new leaves…. All is not lost—just delayed—as when I saw the problem developing I started six new cups of seeds, and those plants are about two inches tall and I’m looking forward to transplanting them later this week.”
When transplanting day came yet again, I went about pulling out the damaged plants and suddenly had a shocking thought. This is an herbicide drift problem, and no one is using herbicide in the neighborhood. Could I be causing the problem? What about that bag of fertilizer that I have been using—the one a neighbor gave me when he moved away last year? I had seen the N-P-K figures and had skimmed over all the big print on the bag.
But did I read everything? I almost ran to the garage and looked at the front of the bag—and it gave no hint of herbicide. But on the back, in small print at the bottom, a box eventually got around to the point that the fertilizer contained 2,4-D, mecoprop, and dicamba, three herbicides.
Oh, no! I was shocked! I had been sprinkling death pellets into my tomato-planting holes all spring. Herbicide drift? No, it was herbicide intake through each tomato’s root system.
I am embarrassed, of course. One rule every Master Gardener learns during initial training classes is “Read the label.”
I thought I had read the label—but I hadn’t read the fine print—just the big stuff.
And my tomato plants curled and twisted and ended up in the trash bucket.
I confessed to my crime to the Expert at the Home & Garden Information Center and explained that I had tried to shovel out polluted soil from the planting areas and wondered how long the problem might persist.
“Helluva story, Bob,” the Expert replied. “The three herbicides have been shown to break down within 60 days (dependent on sufficient soil temperature, moisture, and organic matter) so no worries for planting later this summer or next year.”
The good news is that my latest tomato transplants are nicely growing—but three weeks behind in the size they should have been. But the fact remains that I was guilty of tomatocide. I should have read the fine print.
And I have excellent advice for every gardener: Read the Label—All of It!