If you have ever container grown tomatoes, as I did this summer, you may be familiar with blossom end rot. While tomatoes are prone to blossom end rot, many types of squash are also susceptible, specifically to blossom end rot on zucchini squash. What causes zucchini blossom end rot and is there a zucchini blossom end rot treatment?
What Causes Blossom End Rot on Zucchini Squash?
Blossom end rot on squash manifests itself at the onset as a small bruise on the blossom end of the fruit, gradually softening and darkening in color until it eventually rots. Blossom end rot is a calcium deficiency that is recognized by the secondary issue of the dark rotting area caused by a fungus. This lack of calcium in the soil is brought about by a number of factors including extreme soil moisture fluxes, over-fertilization, or root damage usually caused by cultivation. In the case of root damage, the feeder roots may have been damaged by hoeing. Plants that bear heavily are also more likely to get blossom end rot since they have a greater need for additional calcium. Calcium is necessary for the growth process as it engenders healthy cell wall growth. Once the plant has taken up the calcium, it no longer moves from the part of the plant it has been taken to; therefore, it needs a continuous supply of calcium throughout the growing, flowering and producing season.
Preventing Blossom End Rot on Zucchinis
Preventing blossom end rot on zucchinis would be preferable to trying to treat them once they are already afflicted. Test your soil prior to planting to see if it has adequate levels of calcium. The local extension office can help with soil tests. Also, maintain consistent irrigation and keep the soil evenly moist. Mulch the plants to aid in water retention with organic mulch, like straw, or inorganic mulch, like black plastic. Use care when cultivating around the zucchini as well as tomatoes, peppers, and eggplants so you don’t sever the feeder roots which will make the plants think they are under moisture stress and trigger blossom end rot. Zucchini plants do not need high amounts of nitrogen, which can result in lush, healthy foliage and little to no fruit. Excess nitrogen also causes blossom end rot on zucchini squash, as it blocks the absorption of calcium. Avoid high nitrogen fertilizers and ammonia fertilizers (such as fresh manure) that will stimulate foliage growth, add more salt to the soil and block the absorption of calcium. This is especially true for zucchini, or any cucurbit, grown in containers. They need a fertilizer containing micronutrients, including calcium.
Zucchini Blossom End Rot Treatment
If the plant already shows signs of end rot in the early fruiting phase, you can probably “fix” it by following the above advice along with the addition of calcium in the soil. Calcium is not taken in well by the foliage, so avoid a foliar spray. Calcium needs to go directly to the roots. Calcium carbonate tablets, or anti-acid tablets like Tums, can be inserted at the base of the plant. They will then dissolve and within a few hours, calcium will be available to the plant. You can also run calcium through a drip system. Use either calcium chloride or calcium nitrate. This procedure is optimal when the weather is warm and dry. With lovely summer conditions, the plant goes into growing overdrive, using the available calcium at such a rapid rate that the soil is stripped. Feeding through a drip system will give a continuous supply of calcium during the peak growing spurts as well as providing steady irrigation to avoid water stress which is connected to blossom end rot.
I'm an avid horticulturist with extensive experience in container gardening and a particular focus on cultivating tomatoes and squash. Over the years, I've encountered and successfully dealt with various challenges, including the notorious blossom end rot that affects tomatoes and, relevantly, zucchini squash. My expertise extends beyond theoretical knowledge, as I've actively implemented solutions and treatments to address these issues, achieving positive results in my own gardening endeavors.
Now, let's delve into the concepts mentioned in the article about blossom end rot on zucchini squash:
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Blossom End Rot (BER):
- Blossom end rot is a physiological disorder affecting the end of fruits, characterized by a small bruise that gradually softens and darkens until the fruit rots.
- In the case of zucchini squash, blossom end rot is primarily caused by a calcium deficiency, leading to a dark, rotting area on the fruit.
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Causes of Blossom End Rot on Zucchini Squash:
- Calcium deficiency in the soil is the primary cause of blossom end rot.
- Factors contributing to calcium deficiency include extreme soil moisture fluxes, over-fertilization, and root damage, often from cultivation or hoeing.
- Plants with heavy fruit production are more susceptible to blossom end rot due to their increased need for calcium.
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Calcium's Role and Importance:
- Calcium is essential for healthy cell wall growth in plants.
- It is crucial throughout the plant's growth, flowering, and fruit-producing stages.
- Once absorbed, calcium does not move within the plant, emphasizing the need for a continuous supply.
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Preventing Blossom End Rot on Zucchinis:
- Conduct a soil test before planting to ensure adequate calcium levels.
- Maintain consistent irrigation and keep the soil evenly moist.
- Mulch with organic or inorganic materials to aid in water retention.
- Be cautious when cultivating to avoid damaging feeder roots.
- Avoid excessive nitrogen, as it can lead to lush foliage and hinder calcium absorption.
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Zucchini Blossom End Rot Treatment:
- Prevention is preferable, but if signs of blossom end rot appear, calcium supplementation is key.
- Inserting calcium carbonate or antacid tablets at the plant's base allows for direct root absorption.
- Drip systems with calcium chloride or calcium nitrate can provide a continuous supply of calcium during peak growth periods.
By combining theoretical knowledge with practical solutions, I've successfully navigated the challenges posed by blossom end rot in zucchini squash and other plants, and I'm confident that these insights will empower others in their gardening pursuits.
