As the weather begins to rise in the summer, you may notice that yellow flowers falling off the tomato plants one by one each day before the tomatoes develop.
And of course, there are no flowers.
Flower drops occur throughout the summer in both heirloom and hybrid tomato types, but are rarely caused by pests or diseases. It is especially common in hot or dry climates, and even if the grape grapes continue to grow and steal their leaves, the flowers may never hang long enough to pollinate.
Can you do anything about it? Yes – it starts with understanding why Blossom Drops happen in the first place.
The most common reason is high temperatures.
Does that surprise you? I’ve always heard that tomatoes are (and yes) frost sensitive, but they don’t love high fever either. They are not hot climate crops, they are warm weather crops.
When daytime temperatures soar above 85°F and nighttime temperatures consistently exceed 70°F, pollen becomes unfeasible. Pollination does not occur, so the flowers shrink and fall off.
Conversely, low temperatures can also affect pollination. If nighttime temperatures are consistently below 55°F, this will make pollen unfeasible and reduce flowers. (The flowers are sometimes still pollinated, but the resulting tomato fruits suffer from physical deformations called cat faces.)
A lack of water is another common reason for the depletion of flowers. If your plants don’t get a good deep soak every week, the fruit set will suffer. Inconsistent watering is also the main cause of another tomato disease called Blossom End Rot (which, contrary to popular belief, cannot be fixed simply by adding calcium).
Not so much, but:
Excessive winds that physically damage the flowers can physically damage the wind and poor pollination by pollinators to excessive nitrogen bloat. This promotes leaf growth at the expense of a heavy fruit set of fruit production. This usually produces flowers (there is not enough energy to set up the fruit while establishing the roots and leaves).
So, what can you do about Blossom Drop?
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First, timing is everything
If you live in hot climates like Hawaii, Arizona, Texas, Louisiana, Alabama, Florida, and other parts of the south and southwest, it is important to plant tomatoes early to ensure rich crops. Transplanting in late winter to early spring will prevent excessive heat arriving by June, and will promote healthy flower and fruit production.
If, like me, you live in a high desert climate where frosts are seen in late spring, resist the temptation to bring out your plants earlier. If the overnight low is still in Fahrenheit in your 40s, you’re always ready to cover it with a frost cloth.
One trick to use when you want to plant early is to use tomato teepees (originally known as “wall ‘o water”) filled with these water around the plant. They are a must for gardeners living in cool climates!
(Side note: I own more than 20 of these insulated walls, some of which have been awake all summer each year in my harsh climate. You can find many cheap imitations on Amazon, but I would recommend that I use them personally and be durable.
The kindergarten collects heat during the day, releases warmth at night, stabilizes temperatures, and protects plants from chills. You need to maintain them until the leaves start to grow from the top.
I have been using tomato teepee in Oregon’s central gardens for almost 10 years (that last frost is usually mid-June). We were able to safely transplant the tomatoes outside in mid-May. Many people here will have to replace their frostbite plants in June, but mine is lush, healthy and fertile.
Choose the right tomato variety
If flower drops are a constant problem in your garden, consider trying new cultivars.
In hot climates, a short and early satisfaction tomato variety will give you the best results. These are usually recommended for gardeners in short growing seasons, but are also ideal for gardens looking at the temperature of the triple girders in the summer.
Short season tomatoes mature within 70 days (and sometimes as many as 50 days) and can get a good harvest before temperatures rise.
You can also consider cultivating heat set tomatoes, a variety that has been specially raised for heat tolerance. These types of tomatoes usually don’t have a hard time setting fruit at high temperatures, and one variety I love and grow every year is both heat-resistant and cold-resistant. (This is my list of recommended heat set tomato varieties.)
If you can’t find heat set tomatoes in your area, consider growing definitive tomatoes (sometimes called bush or patio tomatoes). By setting the fruit at once early in the season, the tomatoes will bang the heat, causing the heat to get intense, allowing you to harvest a considerable amount of tomato before the heat gets too strong.
Another advantage of definitive tomatoes is their size. They are compact enough to grow in containers, and if you place the container in a rolling plant caddy, you can easily move it to a shaded spot in the afternoon to evacuate from the heat.
Give the plants a shade
Speaking of shade, the easiest way to give tomato plants a rest from the heat is to shade them in the afternoon when the day is swell.
I like to drape a shaded cloth (usually 30-40%) over the plants to cool during heat waves. Once it falls back into the 80s Fahrenheit, the shaded fabric falls off.
However, you don’t need to get a special shaded cloth. Old bed sheets, table linens, or existing frost covers can also be used as shade fabric.
I actually keep frost cloth cut into low tunnels all year round. When there is a threat of frost, I roll it to cover the raised bed. If you need to shade new implants or heat-sensitive plants, simply cover the bed in part. Frost cloth is a medium fabric that does not retain heat when used in this way. It simply provides shade and I can feel the temperature has dropped a few degrees while I’m working under it.
Consistently water
Tomatoes need consistent moisture to survive the hot season. Their roots run deep, and the soil is cold and full of nutrients and water is needed there.
Aim to water tomato plants 2-3 times a week (rather than a short daily burst of watering). Consistent watering also helps prevent the edges of the flowers, preventing the skin from cracking.
Multivate your plants well
Mulching helps keep tomato plants healthy by controlling soil moisture and soil temperature. Additionally, if the weather causes wide temperatures to fluctuate between day and night, it reduces stress on the tomatoes.
You can mulch your plants with all sorts of organic ingredients, but my favorite is straw, as it is cheap, easy to source and breaks down during the growing season and feeds the soil.
(I also use sheep wool in my garden, which is highly insulated and adds a little nitrogen to the soil.)
Read more: Here are other types of organic mulch to consider your garden
