Totally confused on lime

kenny_j · April 3, 2012

Trying to follow many recommendations on planting in pots, so I bought some dolomite lime to add to containers. Everything I am reading since buying the lime says to add at least one month prior to planting, and to NOT fertilize soon after addition of lime!! So, do I, or should I add lime to final destination 5 gal pots as I pot the plants? And when can I fertilize. The more I think I learn, the more questions pop up.

kj

rsg2001 · April 4, 2012

Kenny, I'm not an expert, but if you're using Earthboxes, they have you add both the lime and the fertilizer at the same time when you're preparing the pot. Sorry to add to your confusion.... The couple of Earthboxes I have had had good results with that methodology. Most of my containers are self-watering types from Gardener's Supply, and I had never used lime in them... until I had good results with the Earthbox, so now I had that two before planting, along with the fertilizer. I use the dolomitic line - very fine powder.

feldon30 · April 4, 2012

Quote:

Originally Posted by kenny_j

Trying to follow many recommendations on planting in pots, so I bought some dolomite lime to add to containers. Everything I am reading since buying the lime says to add at least one month prior to planting, and to NOT fertilize soon after addition of lime!!

Not sure where you are reading that. Sounds totally silly to me.

Although I was doing raised bed gardening, I added dolomitic lime to the planting hole right before I stuck the plants in the ground, and had great results.

Never heard of having to wait a month.

Elliot · April 4, 2012

We plant our tomatoes in pots and if we don't add calcium in the form of line, we get end rot on the tomatoes. What I do is to add the line to water and water the pots every other week with it. Some people sprinkle it on the soil and let regular watering do its job. The thing to get out if this is that the line is very inexpensive and you don't have to spend on the very expensive brands to get a good result.

Elliot

fortyonenorth · April 4, 2012

Adding lime ahead of time gives it time to react with soil moisture to neutralize soil acidity (i.e. adjust pH). It happens on a bell curve, so while it won't fully react immediately, it accomplishes most of it's neutralizing within a few weeks. Just make sure to water thoroughly.

There is some logic to adding lime separate from your fertilizer. Certain mineral elements in fertlizer, namely phosphorus, will readily react with other elements to form insoluble compounds. For example, calcium + phosphorus=calcium phosphate. Once these compounds are formed, they are unavailable for use by the plant until they are mineralized, or broken-down, by soil microbes. That's the logic, at least - and it's probably advisable if you are fertilizing acres. However, from a practical standpoint, I don't think it makes a whole lot of sense to add lime and ferts separately when you're potting-up 5 gal containers.

Ruth_10 · April 4, 2012

Second fortyonenorth. Dolomitic lime is not immediately available to the soil. Think of it as slow release mineral.

kenny_j · April 4, 2012

Still confused but not as much!!! I bought the lime for the 5 gal grow bags, so, like raybo, I will do half with and half without and see what happens. Tested my in ground garden I have been growing in for 15 yrs now, and soil was perfectly neutral, surprised, but I amend it yearly with leaves and compost, and plant winter rye in fall, so nothing needed their. I do get occasional BER, but not much. What I had read at several sights when I googled lime, was fertilizer is acidic, and lime would just react immediately with it to neutralize the fertilizer. But I had read here that many add to pots especially to avoid BER. Thnx for all the replies. Think I will try Feldons Idea and add a little to half the inground plants also.

Duets · April 5, 2012

Quote:

Originally Posted by kenny_j

Still confused but not as much!!! I bought the lime for the 5 gal grow bags, so, like raybo, I will do half with and half without and see what happens. Tested my in ground garden I have been growing in for 15 yrs now, and soil was perfectly neutral, surprised, but I amend it yearly with leaves and compost, and plant winter rye in fall, so nothing needed their. I do get occasional BER, but not much. What I had read at several sights when I googled lime, was fertilizer is acidic, and lime would just react immediately with it to neutralize the fertilizer. But I had read here that many add to pots especially to avoid BER. Thnx for all the replies. Think I will try Feldons Idea and add a little to half the inground plants also.

Kenny, you are no more confused as I am! I'm now trying to read up on when & how much lime to add. The only conclusion I can come up with is.....if you happen to add too much lime by mistake, just go to the grocery store & pick up some "Lime-Away" LOL....[just kidding]

fortyonenorth · April 5, 2012

Here's a real quick primer on lime use.

There are two main types of lime: ag lime (also called hi-cal lime) and dolomitic lime. Both contain calcium carbonate and magnesium carbonate. The main difference is that ag lime has very little magnesium (2-5% perhaps), while dolomite has a much great amount of magnesium - 11% is typical. The precise % of calcium and magnesium in any product is going to vary because limestone is mined in many parts of the country and different quarries have different quality material.

Lime has two purposes:

To raise the pH of acidic soils so that it is in a range which enables optimal uptake of nutrients by plants. Some nutrients are more "available" at low pH and some are more available at higher pH. A good range--where most nutrients are easily available is 6.0 - 6.8. Much higher than that and micronutrients are increasingly unavailable; much lower than that and some nutrients are so easily available to the plant that toxicities occur.

The second purpose of lime is as a source of calcium and magnesium. These are both very important macronutrients and are lacking from most NPK fertilizers.

Because both calcium carbonate and magnesium carbonate influence soil pH it is entirely possible to have an optimal pH and have a deficiency or excess of either calcium or magnesium. If you have low pH and low magnesium levels and simply add high-cal lime you will raise your soil pH but you'll still be short on magnesium. Conversely, if you're OK on magnesium but short on calcium and use dolomite lime to raise your pH, you will simultaneously create an excess of magnesium which, in turn, will create problems with uptake of calcium.

It's advisable to maintain a ratio of Ca:Mg of roughly 7:1 by weight - this would represent the ratio of Ca:Mg present in your soil or potting mix, NOT the ratio to add. Remember, your soil/mix already has some Ca and Mg, we're just adding more. BTW, some folks say that plants will tolerate a much wider range of Ca:Mg, but it's universally agreed that you always want to have more calcium than magnesium in your soil.

Most soils which are rich in organic matter are naturally acidic. This is especially true of potting "soils" which are usually comprised of significant amounts of bark and peat. So, adding lime will be desirable. How much to add? Well, if you're growing in the ground, I'd definitely get a soil test to find out how much calcium and magnesium are already in the soil. If you rely solely on pH to determine whether or not to add lime, you run the risk of getting it wrong for the reasons described above. Adding lime when you don't know anything about your soil pH and/or nutrient components is pure folly.

If you're growing in containers, it's tough to know exactly what type of lime to add and how much. I recently concocted a batch of 8 parts pine bark fines, 1 part peat-based soil, 1 part Turface, 1 part perlite. The natural pH of this mix was 5.6. Based on a soil test I was required to add about 1. 5 oz. of dolomite lime per cubic foot of soil and 1 oz. of hi-cal lime per cubic foot of soil. This isn't a whole lot - maybe a 1/4 cup total of pelletized lime, it bit less if it's pulverized. This is optimal. If you want to simply by not adding two different types of lime, just add dolomite. It will get you in the ballpark.

kenny_j · April 7, 2012

Thanx 41, and everyone else. The picture is coming into focus!!!

April 3, 2012	#1
kenny_j Tomatovillian™ Join Date: Sep 2011 Location: holly michigan Posts: 380	Totally confused on lime Trying to follow many recommendations on planting in pots, so I bought some dolomite lime to add to containers. Everything I am reading since buying the lime says to add at least one month prior to planting, and to NOT fertilize soon after addition of lime!! So, do I, or should I add lime to final destination 5 gal pots as I pot the plants? And when can I fertilize. The more I think I learn, the more questions pop up. kj

April 4, 2012	#5
fortyonenorth Tomatovillian™ Join Date: Jan 2010 Location: NW Indiana Posts: 1,150	Adding lime ahead of time gives it time to react with soil moisture to neutralize soil acidity (i.e. adjust pH). It happens on a bell curve, so while it won't fully react immediately, it accomplishes most of it's neutralizing within a few weeks. Just make sure to water thoroughly. There is some logic to adding lime separate from your fertilizer. Certain mineral elements in fertlizer, namely phosphorus, will readily react with other elements to form insoluble compounds. For example, calcium + phosphorus=calcium phosphate. Once these compounds are formed, they are unavailable for use by the plant until they are mineralized, or broken-down, by soil microbes. That's the logic, at least - and it's probably advisable if you are fertilizing acres. However, from a practical standpoint, I don't think it makes a whole lot of sense to add lime and ferts separately when you're potting-up 5 gal containers. Last edited by fortyonenorth; April 4, 2012 at 04:57 PM.

April 4, 2012	#6
Ruth_10 Tomatovillian™ Join Date: Feb 2006 Location: MO z6a near St. Louis Posts: 1,349	Second fortyonenorth. Dolomitic lime is not immediately available to the soil. Think of it as slow release mineral. __________________ --Ruth Some say the glass half-full. Others say the glass is half-empty. To an engineer, it’s twice as big as it needs to be.

April 4, 2012	#2
rsg2001 Tomatovillian™ Join Date: Jun 2006 Location: New York Zone 6 Posts: 479	Kenny, I'm not an expert, but if you're using Earthboxes, they have you add both the lime and the fertilizer at the same time when you're preparing the pot. Sorry to add to your confusion.... The couple of Earthboxes I have had had good results with that methodology. Most of my containers are self-watering types from Gardener's Supply, and I had never used lime in them... until I had good results with the Earthbox, so now I had that two before planting, along with the fertilizer. I use the dolomitic line - very fine powder.

April 4, 2012	#4
Elliot Tomatovillian™ Join Date: Mar 2008 Location: Hicksville, New York Posts: 503	We plant our tomatoes in pots and if we don't add calcium in the form of line, we get end rot on the tomatoes. What I do is to add the line to water and water the pots every other week with it. Some people sprinkle it on the soil and let regular watering do its job. The thing to get out if this is that the line is very inexpensive and you don't have to spend on the very expensive brands to get a good result. Elliot

April 5, 2012	#9
fortyonenorth Tomatovillian™ Join Date: Jan 2010 Location: NW Indiana Posts: 1,150	Here's a real quick primer on lime use. There are two main types of lime: ag lime (also called hi-cal lime) and dolomitic lime. Both contain calcium carbonate and magnesium carbonate. The main difference is that ag lime has very little magnesium (2-5% perhaps), while dolomite has a much great amount of magnesium - 11% is typical. The precise % of calcium and magnesium in any product is going to vary because limestone is mined in many parts of the country and different quarries have different quality material. Lime has two purposes: To raise the pH of acidic soils so that it is in a range which enables optimal uptake of nutrients by plants. Some nutrients are more "available" at low pH and some are more available at higher pH. A good range--where most nutrients are easily available is 6.0 - 6.8. Much higher than that and micronutrients are increasingly unavailable; much lower than that and some nutrients are so easily available to the plant that toxicities occur. The second purpose of lime is as a source of calcium and magnesium. These are both very important macronutrients and are lacking from most NPK fertilizers. Because both calcium carbonate and magnesium carbonate influence soil pH it is entirely possible to have an optimal pH and have a deficiency or excess of either calcium or magnesium. If you have low pH and low magnesium levels and simply add high-cal lime you will raise your soil pH but you'll still be short on magnesium. Conversely, if you're OK on magnesium but short on calcium and use dolomite lime to raise your pH, you will simultaneously create an excess of magnesium which, in turn, will create problems with uptake of calcium. It's advisable to maintain a ratio of Ca:Mg of roughly 7:1 by weight - this would represent the ratio of Ca:Mg present in your soil or potting mix, NOT the ratio to add. Remember, your soil/mix already has some Ca and Mg, we're just adding more. BTW, some folks say that plants will tolerate a much wider range of Ca:Mg, but it's universally agreed that you always want to have more calcium than magnesium in your soil. Most soils which are rich in organic matter are naturally acidic. This is especially true of potting "soils" which are usually comprised of significant amounts of bark and peat. So, adding lime will be desirable. How much to add? Well, if you're growing in the ground, I'd definitely get a soil test to find out how much calcium and magnesium are already in the soil. If you rely solely on pH to determine whether or not to add lime, you run the risk of getting it wrong for the reasons described above. Adding lime when you don't know anything about your soil pH and/or nutrient components is pure folly. If you're growing in containers, it's tough to know exactly what type of lime to add and how much. I recently concocted a batch of 8 parts pine bark fines, 1 part peat-based soil, 1 part Turface, 1 part perlite. The natural pH of this mix was 5.6. Based on a soil test I was required to add about 1. 5 oz. of dolomite lime per cubic foot of soil and 1 oz. of hi-cal lime per cubic foot of soil. This isn't a whole lot - maybe a 1/4 cup total of pelletized lime, it bit less if it's pulverized. This is optimal. If you want to simply by not adding two different types of lime, just add dolomite. It will get you in the ballpark.

April 7, 2012	#10
kenny_j Tomatovillian™ Join Date: Sep 2011 Location: holly michigan Posts: 380	Thanx 41, and everyone else. The picture is coming into focus!!!