Soil Test Questions

JessieC · 2023-04-03T20:54:15+00:00

Hello Everyone, I wonder if you can help me figure out a very surprising soil test. I had one done last year, and noted that my P and K values were on the hi...

Teddahlia

"5.6 pH (I amended with some lime, just a bit)"
The pH of 5.6 is very acid and a bit of lime will not change it that much. If you do not add more lime it only means that you need a bit more fertilizer as acid pH inhibits the uptake of fertilizer.

bloomhjelm

Teddahlia

I did get recommendations from the test provider (King County Conservation) on lime amendment rates for 5.6 pH and what I mean to say is I did not treat them with as much lime as suggested, presuming their rates for "flowers" were based on a more alkaline pH than dahlias prefer. It still may not have been enough and since my nitrogen is so low it does sound like a good idea to add more fertilizer.

SteveM

JessieC I'm disappointed that the pH has gone from 6.5 to 7.0. Anyone have ideas about that?

Jessie, I had a similar soil report last year and had good results supplying the nitrogen with Ammonium Sulfate 21-0-0. The sulfur will also help in lowering your pH. I like it because it is cheap and dissolves completely in water so I can use it in my injector without plugging up the drip tape. If you get it at the big box store make sure it does not include a "weed-and-feed" ingredient that many of the lawn ferts have. You want only Ammonium Sulfate (21-0-0).

JessieC

SteveM
Oh that is so helpful Steve. Thank you! I was about to ask “how do you find the fertilizer without added P?” And of course I wonder what will help the pH too.
I’ll look for that.
And Flowernut Thank you for that insight. I don’t know if I have seen alfalfa meal, but I think I’ve heard of it. Does it attract critters?
Teddahlia Most helpful, as always. Thank you!!

Flowernut

JessieC I've never had a problem with the alfalfa meal attracting critters. Although the only critters I have to deal with is my dog and the rabbits. I used blood meal one year and all 4 of my dogs had a field day!

calico20hill

You can get either Alfalfa pelllets or meal at any animal feed store....like a hardware store that also sells animal feed. The pellets are just ground alfalfa presed into pellets for ease of handling. Either one works fine. I just mix some into the dirt at the bottom of the hole before planting my tuber or plant. You could also dig it into the whole bed if you want. Or scatter it over the surface then rototill. I find it easier to add a scoop at the bottom of the planting hole and stir it up a little.

Teddahlia

"You want only Ammonium Sulfate (21-0-0)"
This chemical is almost poison on acidic soils like ours. It is the most acidic of all the nitrogen fertilizers. If you have alkaline soil it is good. If your soil acidic it is bad. Cheap fertilizers that are sold here have it as an ingredient. It would be OK if you added the same weight in lime as you apply it.

JessieC

Flowernut My main critters are two (lazy) dogs and bunnies that visit (probably because the dogs are lazy.) For some reason I thought that alfalfa meal was bunny food. I did try feather meal once and the dogs were delighted! 🙄

Teddahlia

One of the treatments for voles involves using the castor oil meal they sell at the farm store . It is so bad tasting no dog or vole or gopher will eat anything near it. So, some alfalfa pellets, some blood meal , some chicken feather meal and a nice dose of castor been oil in the hole. Oh, maybe a tuber should go in there too. 😳

JessieC

@SteveM and @Teddahlia Any thoughts on this? It’s the closest thing I can find locally!
Thanks

Teddahlia

They are selling almost all sulfur coted urea and charging more as there is a bit of potassium. Farm stores sell 50 pound bags of strait SC Urea and currently the price is $33.00 at our farm store.

JessieC

Teddahlia Alas, I have nowhere to keep that much, and it would take me years to use up! Is there any harm in the added ingredients??
ETA I think it was about $20 for the 15lb bag. Also, it’s about a mile away. I checked Tractor Supply and the local Feed & seed too.

SteveM

JessieC Is there any harm in the added ingredients??

Your levels of iron are already very high so I would have to do some research to determine if using this formula puts your soil at toxic levels for iron. Too much Iron can interfere with the root uptake of Manganese (Mn). I order Ammonium Sulfate from Home Depot for $17/15lb. (I get free shipping)

JessieC

SteveM ok that’s super helpful. I was lucky at this store in my search for solid brass “quick connect” hose fittings, which I wasn’t able to find elsewhere. I’m glad I resisted the fertilizer. Thank you!

JessieC

Hi again @SteveM and @Teddahlia (or anyone else!)
I did get the proper 21-0-0 fertilizer and wonder if you can advise from here...I don't have a fertigation system in my drip setup, but it's a small enough area that I can dissolve it in water and use a large watering can (or two.)
Given that it's been very hot and dry, but is about to be very wet, what do you suggest? I've got tubers in the ground for the most part, and almost all were pre-sprouted. We are expecting* rain for the next week. I added the * because it's very unpredictable here at the foot of the Blue Ridge, and becoming more so all the time. It doesn't look like a deluge, and may turn out to be very little.
Would you go ahead and get the fertlizer into the soil now, or wait another week?
As a reminder, my pH is 7.0 in the main raised bed. I suspect it is above 7.0 in my smaller beds, because it has been in the past. So it's not just about providing N, but also about tweaking the pH a bit.
Thank you!
Here is a photo of what I bought, btw.

SteveM

JessieC Would you go ahead and get the fertlizer into the soil now, or wait another week?

I don't see any need to hurry with your fertilizer application. Couple of points:

Likely, most of your tubers do not have feeder roots yet and are living off the tuber. I would wait until the plants are up about 6" (or so) before I added any nitrogen. If you add it now and get lots of rain, most of the N could leech out before the plants have roots. If you have cuttings you could fertilize those plants now if you want. I would use their recommendation of 1 tsp/plant worked into the top few inches of soil and water in. Keep the fertilizer 5-6' from the stem to avoid burn. If you disove first, and use a watering can, do not water the foliage or stem.
Your soils' "estimated N release" looks good so, depending on your summer temps and moisture, there is a chance your plants would grow just fine without any fertilizer at all. The N you are adding is for fine-tuning and lowering the pH. As a guideline, I would add the 1 tsp./plant rate about every month during the early months of the growing season.

Teddahlia

As you can see Ammonium Sulfate is one of the most acid fertilizers of all and is about 40% more acid than the urea I use. Good choice for your soil that is too alkaline(but not that bad!)

JessieC

SteveM Brilliant! Thank you. I do have cuttings, but am waiting to put them into the ground. They have their own row, so I can water them differently as needed. I’ve also got some stragglers from last year. I experimented with letting some stay in the ground, and the ones I decided to keep are looking quite good. It remains to be seen how they will fare through the rest of the season, but it’s always good to experiment.
And @Teddahlia That is a fascinating tidbit! I struggled with soil pH above 7 for a few years, and wasn’t sure how to bring it down. When the soil for these beds was delivered in early 2023, I was delighted to see that it was 6.7. Alas, it is creeping up. Good to know I have the right amendment. It looks like the sulfur level also went way down over the course of a year, so I imagine this will help.
As always, thank you for your advice. I will leave you with two pictures (one with a dahlia,) of my dear three legged dog Pancho, who turned 15 this week.

Teddahlia

Soil too alkaline: The standard answer is elemental sulfur and it is converted to sulfuric acid(they use sulfuric acid at a major greenhouse here but in minuscule amounts) and it acidifies the soil and if your soil is deficient in sulfur(as is mine and sulfur could be included on the list of required fertilizers) it adds the needed sulfur to the soil. But you say, "I do not want to use chemicals on my garden." Believe it or not, it is certified organic. However, there are people who are allergic to sulfur and they should not be exposed to it. On the opposite side of acidity. lime is the organic remedy for acid soil. Both are organic soil additives.

Juliarugula

I got back the results of the first soil testing I’ve ever had done in my garden, and I was hoping I could get some feedback. Sample one is a combo of spots in my general dahlia garden area, while sample 2 is a combo of samples taken along a fence line where I observe less vigorous growth. However, as I’m looking over the results, sample 2 actually seems more ideal? Let me know if you guys concur. It makes me think the issue is probably one of light/air flow blocked by the fence, heat reflected from the fence, or possibly I need to reevaluate my watering system at that location.

Reviewing the results, in general it looks like phosphorous is a bit high, but not crazy. A bit high on organic material (I mulch with fall leaf clippings). Ph is a bit high. Anything I missed? Suggestions?

SteveM

Juliarugula However, as I’m looking over the results, sample 2 actually seems more ideal? Let me know if you guys concur. It makes me think the issue is probably one of light/air flow blocked by the fence, heat reflected from the fence, or possibly I need to reevaluate my watering system at that location.

I agree with your evaluation and would consider the variables you mentioned when growing along the fence.

Also, I wouldn't add any fertilizer with phosphorus, including manures, until future tests indicate a need for phosphorus.

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