Fixing Phosphorous Depletion In Raised Beds

[Invisible Girl]

Hi folks. I'm looking for some advice. I have four large redwood containers that I've been using for about 5 years to grow vegetables. They are 8'X4' feet and 2' high.

The nitrogen is fine and the potassium is in surplus, but all three beds are completely lacking in phosphorous. I tried last year to add dry fertilizers to the soil--I think I tried bat guano, blood meal, and "super phosphate" but I don't know that it made much of a difference. Perhaps it was enough to help my plants limp along. I saw a HUGE drop in plant productivity, particularly in beans and tomatoes.

Anyway, I want to fix this problem, but am not sure how to go about it. Because these are raised bed (I have a vole problem) the soil doesn't renew like it would if I were planting directly into the ground, and it can be frustrating. I have a cover crop on my beds now, and I plan to add fertilizers in the spring. What would you recommend for phosphorous?

 

[Chuck]

Hi folks. I'm looking for some advice. I have four large redwood containers that I've been using for about 5 years to grow vegetables. They are 8'X4' feet and 2' high.

The nitrogen is fine and the potassium is in surplus, but all three beds are completely lacking in phosphorous. I tried last year to add dry fertilizers to the soil--I think I tried bat guano, blood meal, and "super phosphate" but I don't know that it made much of a difference. Perhaps it was enough to help my plants limp along. I saw a HUGE drop in plant productivity, particularly in beans and tomatoes.

Anyway, I want to fix this problem, but am not sure how to go about it. Because these are raised bed (I have a vole problem) the soil doesn't renew like it would if I were planting directly into the ground, and it can be frustrating. I have a cover crop on my beds now, and I plan to add fertilizers in the spring. What would you recommend for phosphorous?

Bone meal and rock phosphate are the best solutions but good compost and manures are other good sources as well

 

[Invisible Girl]

Bone meal and rock phosphate are the best solutions but good compost and manures are other good sources as well

Thanks! How much do you think I should put in the beds to make a difference?

 

[Chuck]

Thanks! How much do you think I should put in the beds to make a difference?

I would till in 25lbs per bed and then test. You will probably need more

 

[Invisible Girl]

thanks again

 

[Chuck]

thanks again

I forgot to mention that bone meal is NOT fast acting. I think you would be better off with the rock phosphate. To give you an idea of how much to use I put a big handful into the bottom of each tomato transplant hole. Another thing you can do is sprinkle epsom salts over your planting area.

 

[Invisible Girl]

Ok that's really helpful. I tried the epsom salt mid-year and noticed the plants perked up right away, which makes sense.

What do you think caused the depletion? I've been putting a variety of vegetables in there, and they tend to get big with nice root system. I could understand if the soil were completely depleted, but that's not the case. Why would this nutrient be so low and the other two fine or in surplus?

 

[Chuck]

Ok that's really helpful. I tried the epsom salt mid-year and noticed the plants perked up right away, which makes sense.

What do you think caused the depletion? I've been putting a variety of vegetables in there, and they tend to get big with nice root system. I could understand if the soil were completely depleted, but that's not the case. Why would this nutrient be so low and the other two fine or in surplus?

What have you been fertilizing with and what if anything have you added to the soil over the years?

 

[Invisible Girl]

I usually grow a cover crop of vetch and fava beans, which I cut down and dig into the soil. (It also keeps cats out of the boxes.) Then in the spring I add a combination of compost and cow manure. I've also tried bone meal, but maybe not enough of it.

 

[Chuck]

I usually grow a cover crop of vetch and fava beans, which I cut down and dig into the soil. (It also keeps cats out of the boxes.) Then in the spring I add a combination of compost and cow manure. I've also tried bone meal, but maybe not enough of it.

By doing that you shouldn't be depleted of phosphorus. What it sounds like is that your plants are not able to uptake it. Was you soil test done professionally or did you do it with one of those test kits? If you soil is alkaline or above 7.2 ph I would bet that your plants are unable to uptake and epsom salts will cure your problem. I have never heard of well cared for soil being depleted...........of anything.

 

[Invisible Girl]

Wow, okay. I used the kits with the different colored capsules. I'll check out the PH.

 

[Chuck]

Wow, okay. I used the kits with the different colored capsules. I'll check out the PH.

do Epsom Salts and forget the rest. If you put too much phosphorous into the soil it will mess up the iron and you will get chlorosis and bad leaf drop. Please update your profile to let us all know where you are located and your hardiness zone

 

[Invisible Girl]

Ok. I will. Thanks again.

 

[Fernsdaddy]

I put bone meal in my raised beds at the end of the season it give it a chance to do its thing all winter I also add compost in the spring, Epsom salt helps my egg plants grow bigger and better fruit,