Slow growth

chancethegardener · October 12, 2011

I have been observing slow growth with some vegetables this fall. Radishes don't develop roots, lettuce and Swiss chard grow very slowly. What I did different than last season: before, I was using organic garden soil that has some peat moss in it, for fall I added a good amount of peat moss to each bed. The content of the beds is given below:
- Peat moss
- Compost (composted cow manure, earthworm castings, mushroom compost)
- Vermiculite
- Azomite (this was already in the beds)
I also watered the beds with Great White mycorrhizae.

Do you think peat moss drastically changed pH in a way that some of my vegetables don't like it? Any ideas regarding the slow growth?

RayR · October 12, 2011

It's very possible that the PH is too low and that causes nutrient uptake problems with many plants that don't like acidic soils. You didn't add any lime to the mix I assume?

chancethegardener · October 12, 2011

Hi RayR, no I didn't add lime into beds. I remembered that I have one of those soil test packs. I used it to test pH. I am not sure how accurate this is about the color I get says pH is around 7.0 (neutral). Do you think I should add lime every time I prepare the beds for planting? If so, how much and how often should I apply? Also is there a way to adjust pH after vegetables are planted (e.g. a liquid solutions, or soluble powder)? Does it work if I feed the plants epsom salt every 3-4 weeks?

RayR · October 13, 2011

I don't know how accurate the soil test pack is, I've seen people get mixed results with them because they are limited in their ability to test soil PH accurately in all cases, definitively not as accurate as a proper lab test that would be able to determine both the active acidity and reserve acidity of the soil.
Assuming the results from the soil pack test are close enough to accurate, maybe you have something else going on, you are in Tampa, I'm in the cooler fall temps of the North so I don't know what it's like to grow cool weather crops like Lettuce and Radish or even more temperature tolerant crops like Chard in the far South in fall. Your fall temperatures are more like our summer temperatures I think and I know how difficult it is to grow lettuce and radish up here in the heat of the summer.

I don't even bother until it cools off! But since you've done it before successfully...you know more about your growing climate than I do.
Also, besides the added peat this year, did you replenish the nutrients in the beds this year?

If you suspect there is a low PH problem, then adding a little lime to the soil won't hurt as an experiment. (BTW..Epsom Salts (Magnesium Sulfate) won't to anything to alter soil PH.) You can adjust pH after vegetables are planted, I've had to do this myself. Dolomite Lime (Calcium Magnesium Carbonate) is the safest thing to use, all carbonates will neutralize excess hydrogen ions in the soil water, but Dolomite just reacts slower and is longer lasting. You don't want to use any fast acting lime.
I just mix about 1 heaping Tablespoon of Dolomite Lime per gallon of water and water around the drip line of the plant. I applied this only once to adjust for low PH problems and Calcium and Magnesium deficiency problems with great results.
I've never had to add any more the whole season. You don't want to use too much as you can cause your soil PH to go way too high. Dolomite is usually sold in pellets, but it really is a finely ground powder made into pellets. They break up in water rather quickly and the fine suspension of the particles in water will penetrate into the soil just great.

chancethegardener · October 14, 2011

Yes, I replenish the beds with nutrients every season.
This is very useful information RayR, thanks for your time!

October 12, 2011	#1
chancethegardener Tomatovillian™ Join Date: Jan 2011 Location: WV Posts: 604	Slow growth I have been observing slow growth with some vegetables this fall. Radishes don't develop roots, lettuce and Swiss chard grow very slowly. What I did different than last season: before, I was using organic garden soil that has some peat moss in it, for fall I added a good amount of peat moss to each bed. The content of the beds is given below: - Peat moss - Compost (composted cow manure, earthworm castings, mushroom compost) - Vermiculite - Azomite (this was already in the beds) I also watered the beds with Great White mycorrhizae. Do you think peat moss drastically changed pH in a way that some of my vegetables don't like it? Any ideas regarding the slow growth?

October 12, 2011	#2
RayR Tomatovillian™ Join Date: Jun 2010 Location: Cheektowaga, NY Posts: 2,466	It's very possible that the PH is too low and that causes nutrient uptake problems with many plants that don't like acidic soils. You didn't add any lime to the mix I assume?

October 13, 2011	#4
RayR Tomatovillian™ Join Date: Jun 2010 Location: Cheektowaga, NY Posts: 2,466	I don't know how accurate the soil test pack is, I've seen people get mixed results with them because they are limited in their ability to test soil PH accurately in all cases, definitively not as accurate as a proper lab test that would be able to determine both the active acidity and reserve acidity of the soil. Assuming the results from the soil pack test are close enough to accurate, maybe you have something else going on, you are in Tampa, I'm in the cooler fall temps of the North so I don't know what it's like to grow cool weather crops like Lettuce and Radish or even more temperature tolerant crops like Chard in the far South in fall. Your fall temperatures are more like our summer temperatures I think and I know how difficult it is to grow lettuce and radish up here in the heat of the summer. I don't even bother until it cools off! But since you've done it before successfully...you know more about your growing climate than I do. Also, besides the added peat this year, did you replenish the nutrients in the beds this year? If you suspect there is a low PH problem, then adding a little lime to the soil won't hurt as an experiment. (BTW..Epsom Salts (Magnesium Sulfate) won't to anything to alter soil PH.) You can adjust pH after vegetables are planted, I've had to do this myself. Dolomite Lime (Calcium Magnesium Carbonate) is the safest thing to use, all carbonates will neutralize excess hydrogen ions in the soil water, but Dolomite just reacts slower and is longer lasting. You don't want to use any fast acting lime. I just mix about 1 heaping Tablespoon of Dolomite Lime per gallon of water and water around the drip line of the plant. I applied this only once to adjust for low PH problems and Calcium and Magnesium deficiency problems with great results. I've never had to add any more the whole season. You don't want to use too much as you can cause your soil PH to go way too high. Dolomite is usually sold in pellets, but it really is a finely ground powder made into pellets. They break up in water rather quickly and the fine suspension of the particles in water will penetrate into the soil just great.

October 14, 2011	#5
chancethegardener Tomatovillian™ Join Date: Jan 2011 Location: WV Posts: 604	Yes, I replenish the beds with nutrients every season. This is very useful information RayR, thanks for your time!