You may know this scenario too well. You have lovingly cared for your tomato plants and watched how the first delicious fruits of your work developed … just to see how they were destroyed by ugly brown spots at the end of the flower.
This is the dreaded and misnamed flower end rot.
Why named wrong? Because this "rot" has nothing to do with an infection and everything with the incorrect allocation of calcium in the plant. Technically speaking, it is not a "disease" at all, since no pathogens are involved.
But don't just assume that your soil is low in calcium.
The problem can be due to other factors such as the amount of moisture available in the soil and the condition of the roots.
The use of insecticides or fungicides will not solve this problem. Read on to learn how to prevent the end of blight from occurring and if you can do anything once you find it on your tomatoes.
I will cover the following:
What is final blight?
End-of-flower rot is the formation of lesions on the bottom of the fruit that can grow and cover up to a third to half of each tomato. The lesions begin as small, water-soaked areas. They quickly get bigger and darken when the fruits ripen.
When the lesions grow large, they dry out and smooth, become black and leathery. It starts when the fruits are ripe green and start to ripen.
This often happens with the first tomatoes that are produced during the season, while those from later can be good. This is especially true for indefinite varieties, as they produce tomatoes until the end of the season.
Conversely, if you grow certain varieties that produce all of the fruit at the beginning of the season, there is a risk of losing your entire crop.
What are indefinite and certain types of tomatoes? We have a guide that answers exactly this question.
End-of-flower rot occurs more frequently with large types of plums or pastes and is rarely a problem with small varieties of cherry tomatoes.
Instead of being a disease caused by a bacterial or fungal pathogen, it is a physiological disorder caused by insufficient calcium intake.
A little consolation is that the rest of the fruit remains edible, but you certainly couldn't sell it if that were your goal. And cutting away the damaged portions is certainly not ideal if you were hoping to showcase your local crop in salads and on sandwiches.
Although this disorder is less common, it can also be affected pepper, to squeeze, Watermelons, Cucumbers, and aubergine.
Why does that happen?
I can't overdo the importance of calcium for plants. It is important that this nutrient is available to the fruits during their development.
Calcium plays many roles in plant biology, but keeping cell walls together is key.
Think about pectin and how it gels. Without calcium to hold the pectin together in the cell walls, the cells turn into porridge. This is the process that happens when Soft rot bacteria Cause decay, but in this case the plant can rot.
Confused? Don't worry, I'll go into more detail below.
Even worse, once the tissue begins to rot, bacteria and fungi can penetrate and make it even heavier.
Factors that affect a plant's calcium intake include:
- Root injuries
- Heavy use of nitrogen fertilizers
- Fluctuations in soil moisture
Worse at the start of the season
You may be wondering why the first tomatoes of the season grow on plants you have gently nurtured from seeds or planted as seedlings, reward you with damaged fruits.
There are several possible reasons for this.
You could be a problem with the roots. It is important for tomatoes to have a well-developed root system.
The roots absorb calcium from the soil, and ideally the calcium is released through the passage of water through the xylem through the plant.
However, this type of release does not always distribute the calcium evenly in the plant. Sometimes the calcium gets stuck in the stems or leaves and never makes it to the developing fruits.
Tomatoes planted in cold soils may not develop robust root systems.
If the plants have been over-fertilized and have plenty of foliage, they are more likely to develop blight because the leaves compete with the fruits for calcium.
This will help you avoid end-of-flower rot
There are a number of cultural measures you can take to minimize the likelihood that you will be faced with deformed tomatoes at harvest time.
1. Wait until planting
While you are eager to start your tomatoes in the spring, you can set them up for the final blight when you plant in cold soil, or Clay soil that you have not changed properly. Patience is a virtue, they say!
Wait at least two weeks after your last frost date to plant them in your garden. If you do not know when this is the case, you can find it in the Almanac of the old peasant.
It is also important that the soil temperature is at least 60 ° F before planting your seedlings outdoors. You can determine this with a floor thermometer.
Seedlings should have at least two to three sets of real leaves and should be hardened before transplanting.
Read our guide to learn more about it how and when to transplant your seedlings.
2. Fertilize properly
You want the soil pH to be between 6.5 and 7.5, so having yours can be a good idea Garden soil tested before you plant. The results tell you if you need to make any changes.
It is best to use fertilizers that are low in nitrogen but rich in phosphorus. Consider fertilizers with one NPK ratio from 4-12-4 or 5-20-5. If you want to grow your crop in a container, choose a fertilizer specially designed for growing tomatoes.
If you use nitrogen fertilizer, also add calcium nitrate and avoid nitrogen in the form of ammonia or urea.
In general, a lack of calcium in the soil is not the problem – most soils already contain enough calcium. The problem is that the calcium is not properly distributed throughout the plant tissue.
However, if the results of your test indicate that your soil is poor, you need to add calcium to or before planting.
Changing the soil later, or spraying plant foliage on it, cannot fix the problem once it works.
Soils that have been heavily irrigated with poor quality water can develop with an abundance of soluble salts. This is because tap water is often treated with chemicals that can upset the nutrient balance.
This salt concentration can increase the likelihood that plants will develop this condition because the calcium in the soil is less available to the plants. Problem salts include ammonium, sodium, magnesium and potassium.
3. Don't cultivate too closely
It can be surprisingly easy to damage the roots of tomato plants. This can even happen if you do something that seems as harmless as adding piles or cages to the floor.
It is best to add this if you are planting your tomatoes in your garden for the first time before the roots have spread.
Do not cultivate the soil within one foot of the base of the plant. This is especially important after plants have planted fruit.
If you have ground vegetable patches or large raised beds, it should be enough to scrape lightly with a hoe to remove weeds.
4. Keep the soil moisture constant
Tomatoes need at least an inch of water a week during the growing season. This can take the form of rain or irrigation.
Not sure how much precipitation you will get? A rain gauge can help.
When doing additional irrigation, spray at ground level instead of watering the foliage. Use a drinking hose instead of sprinklers. This will also help prevent diseases like premature rot.
If your tomato plants are in containers, you will need to water them more often. Ideally, they should be planted in plastic pots so they don't dry out as much.
A 3 to 4 inch Layer of mulch also helps maintain moisture in the soil. After the plants have been in the soil for 3 to 5 weeks, add an organic mulch, e.g. B. wood chips, grass clippings or straw that is free of weed seeds.
Note that too much moisture can also be a problem. Heavy rains, especially after a dry spell, can drain calcium from your soil and increase the likelihood of this problem.
5. Provide shade
If you have a home garden, you should consider shading your plants when your plants are hit by hot, dry winds. Winds like this can drastically reduce soil moisture.
Even if you prefer one full sun locationIf you live in a very hot climate, you may need to protect them from the sun even when there is no wind.
In fact, gardeners in hot climates routinely shade their tomato plants from 10 a.m. to 2 p.m. in the summer months.
If you have more of a plantation, you can buy a shade roof, such as this one from Home Depot.
Do not give up!
While the appearance of badly damaged fruit can be extremely demoralizing, don't give up hope. If you grow indefinite varieties that bear fruit early and late in the season, the rest of your harvest can be fine with regular watering.
There are also a number of ways you can prevent this problem from affecting the rest of your tomatoes.
Careful planning at the time of planting will help give your tomatoes a boost that will help ensure healthy growth and fruit production throughout the season. Taking local weather conditions and soil moisture into account is a must.
Did your plants develop final blight? Did it affect your entire harvest and what changes did you make during the growing season? Do you have sharing tips? We'd love to hear from you in the comments below!
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