Best way to add calcium to soil to prevent blossom end rot?
Tomato SC
I have a tomato growing question. I have experienced problems with blossom end rot on past tomato crops and I would like to try growing some again this year. If it is caused by a calcium deficiency then what is the best way of supplementing the soil?
Posted
by: Melanie Young
(9 points)
Posted: April 1, 2013
Answers
While blossom end rot is caused by a lack of calcium to the developing fruits, it doesn't mean there isn't enough calcium in the soil. It is most often related to an inconsistent amount of water in the soil or being taken up by the plant. Calcium is brought to the fruit in the water the plant takes up from the soil so allowing the soil to dry out too much between waterings can cause blossom end rot. Pot-grown tomatoes are especially susceptible.
Once fruits begin to form, water to supply 1-2" per week from rain and irrigation combined. Water deeply 1-2 times per week rather than frequent shallow waterings to promote good root growth. Water is drawn into the plant partly in relation to the amount of water lost from the leaves via transpiration. Transpiration slows down when there is high humidity, resulting in less water being needed from the soil. Less water from the soil = less calcium coming into the plant so extended periods of high humidity can also result in blossom end rot.
The best way to see if there is a pH problem or calcium deficiency in the soil is to get a soil test done. The best pH for tomato is 6.0-7.0 and if it's already there, you don't want to add lime which will raise the pH. A mulch can help the soil retain moisture. Other tips include not planting the tomatoes when the soil is too cool (affects early fruits), don't overfertilize with nitrogen, and be careful not to injure the roots if cultivation is needed near the plants. Some sources recommend calcium chloride sprays on the foliage but use caution with these. They can cause plant injury and some reliable sources say they don't really help.
Once fruits begin to form, water to supply 1-2" per week from rain and irrigation combined. Water deeply 1-2 times per week rather than frequent shallow waterings to promote good root growth. Water is drawn into the plant partly in relation to the amount of water lost from the leaves via transpiration. Transpiration slows down when there is high humidity, resulting in less water being needed from the soil. Less water from the soil = less calcium coming into the plant so extended periods of high humidity can also result in blossom end rot.
The best way to see if there is a pH problem or calcium deficiency in the soil is to get a soil test done. The best pH for tomato is 6.0-7.0 and if it's already there, you don't want to add lime which will raise the pH. A mulch can help the soil retain moisture. Other tips include not planting the tomatoes when the soil is too cool (affects early fruits), don't overfertilize with nitrogen, and be careful not to injure the roots if cultivation is needed near the plants. Some sources recommend calcium chloride sprays on the foliage but use caution with these. They can cause plant injury and some reliable sources say they don't really help.
Posted
by: Joan Allen
(6 points)
Posted: April 2, 2013
deactivated commented,
Joan, can you tell us more about the "reliable sources" mentioned at the end? Would be useful to see the resources. over 10 years ago.
Joan, can you tell us more about the "reliable sources" mentioned at the end? Would be useful to see the resources. over 10 years ago.
Joan Allen commented,
http://www.caes.uga.edu/publications/... sorry for delay in responding to this...my 'reliable source' is at this link, a ways down in the article/fact sheet under diagnosis question #2. over 10 years ago.
http://www.caes.uga.edu/publications/... sorry for delay in responding to this...my 'reliable source' is at this link, a ways down in the article/fact sheet under diagnosis question #2. over 10 years ago.
Nicodemas Zabron commented,
I agree with you Joan, from my experience, spraying of calcium based foliar fertilizer alone has no significant effect on the tomato crop but when combined it with any fungicides the burning effect around the leaves margine is more likely to occurs 2 months ago.
I agree with you Joan, from my experience, spraying of calcium based foliar fertilizer alone has no significant effect on the tomato crop but when combined it with any fungicides the burning effect around the leaves margine is more likely to occurs 2 months ago.
Often a deficiency, or lack of availability of Magnesium results in decrease availability thereof, directly influencing the uptake (thus availability) of Calcium. Gypsum indeed functions well in that it results in the release of Magnesium from chelates (bound carbon) resulting in increased Mg/Ca exchangeability, and hence uptake in the plant.
Alternatively, a foliar Calcium application during or just after flowering may suffice. Calcium Metalosate works well.
If you suspect (after soil testing) that the Magnesium levels are low in the soil, add a handful uf Epsom salts to the base surrounding the stem and wash in with water. This will "loosen up" existing Ca in the soil allowing for more effective uptake in the plant.
Ensure that this is done early in the growing period so you can gauge progress.
Alternatively, a foliar Calcium application during or just after flowering may suffice. Calcium Metalosate works well.
If you suspect (after soil testing) that the Magnesium levels are low in the soil, add a handful uf Epsom salts to the base surrounding the stem and wash in with water. This will "loosen up" existing Ca in the soil allowing for more effective uptake in the plant.
Ensure that this is done early in the growing period so you can gauge progress.
Posted
by: Cornelis
(2 points)
Posted: April 4, 2013
Joel D Morris commented,
I always put about a handful of Epsom Salts around my tomato plants and never have a problem with blossom end rot. Simple & effective & cheap. over 8 years ago.
I always put about a handful of Epsom Salts around my tomato plants and never have a problem with blossom end rot. Simple & effective & cheap. over 8 years ago.
I use washed crushed eggshells in water around the tomatoes. Also barn lime placed around the plant when it is about to flower will help sometimes.
Posted
by: chris hedding
(1 point)
Posted: April 1, 2013
Lime and gypsum work well- I use the pelletized stuff because it's easier to use and not a dusty, plus it is coated in molasses, which is another good source of calcium. When you feed your plants, you can add plain yogurt at 2 oz per gallon of water, and molasses as well, for more calcium plus some carbohydrates, at a rate of 2 oz per gallon of water. Eggshells work well, but take a while to break down, so the calcium is not available to the plant right away.
Posted
by: Bradley Cahill
(1 point)
Posted: April 1, 2013
The movement of Calcium from the soil to the plant is only up, like elevator going only up, so if it goes to the leaves then it will stay there and will not go to fruits..... for that is very important to apply Calcium by foliar application specially during fruit set phonological stage not only to solve the problem of blossom end rot, but also to increase the cell division inside the fruit at this stage.... And by foliar application is better Calcium chelated by carboxilic acid to increase the efficiency of Ca movement inside the plant. about 7 years ago.