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...

MissyWeitzel

Teddahlia I got my soil test results back a couple weeks ago. Compared to last year I see improvements in micro elements and my organic matter percentage increased. My plan is to amend with potash and nitrogen granules and just continue adding organic matter via compost and leaf mulch. I'm also planning to try crab meal this year. I have fungal issues in my vegetable garden soil and there are a couple areas in my dahlia beds where I had fungal problems 2 years in a row now so I'm gonna see if just applying crab meal everywhere helps. My local hydroponics store can order me 50lb bags for a good price and I'll just use my spreader to broadcast it.

calico20hill

Teddahlia Well, If I plant my surviving "Tiny Tubers" among the ones with the hardiest tubers, I wonder how many years of crossing genetics it will take to get beautiful flowers with great tubers...? Not sure I will live that long but I will see what I can do. My only idea is to learn not to over water. Oh yes, one other switch I am going to make. I have been planting my seedlings in the first row of the garden where shade arrives the earliest in the afternoon. I am going to flip that and put them at the bottom of the garden where they will get the last sun of the day. Maybe more sunlight will help them.

Teddahlia

Missy's new soil test has shown reduction in phosphorus from 177 to 121. pH the same. Boron a bit low but that is dangerous one to add.

JessieC

Teddahlia Thanks for the reminder, Ted. I’ll get new soil tests soon. I had the soil with too much of everything last year. I did as suggested and did not add anything major. I did have areas where I wonder if I also had too much nitrogen. Some varieties that had thrived and bloomed the previous year gave me nothing but laughably overgrown foliage and a couple of blooms each.
In any event, the new soil tests will be informative, so I’ll get on it!
The burgundy waterlily (or is it purple, or dark red?) in your photo is stunning! And I see Margaret in the background too, if I’m not mistaken.

Teddahlia

Yes, Margaret in the background. Note the flower is above the stake that is five feet above the ground and the other flowers are even higher. This one reaches 6 feet easily and has a huge main stalk. Not the tallest new waterlily however.

calico20hill

How tall IS your tallest waterlily?

Teddahlia

I believe the red 2023 seedling in Margaret's hand crossed waterlily row may be the tallest so far. A well known breeder spotted it during our garden tour and made some positive comments about it even though the flower was way above his head.
I did not measure the height but since it was a first year seedling and it was really tall, it probably will be even taller this year. It is also larger in diameter WL than most , probably 6.5 inches.

bloomhjelm

Teddahlia How big are bowls for floating waterlilies at shows? Can I use a popcorn bowl? 🙂

JessieC

Teddahlia I brought my sample over to the co-op yesterday, so I should have results next week. Thank you for the reminder!
This may belong in another thread, but I recall you saying that a time-release osmocote type fertilizer is best for grow bags. I have about a dozen of those, which are excellent for spares and pot tubers and the inevitable “I forgot I ordered this tuber!” I’ve been mixing garden soil with last year’s grow bag contents, annd I’ll add some time release fertilizer. Anyone else have suggestions for how to provide a good growing medium in a bag?
Last year we were able to put tubers in by April 15. It feels like the right time to start now. Happy planting season, everyone!

Two pictures from last year’s grow bag area.

Teddahlia

I believe the major concerns about the soil in grow bags(I am using our experience with growing dahlias in pots of 15 or 20 gallons but seldom smaller) are the weight of the soil and having healthy soil in the bag. The weight issue is applicable mostly if you plan to move the bags around. Potting soil mixes vary a bit in weight but all of them are lighter in weight than garden soil. The people who grew them on Dahlia Talk said they bought a load of 3 or 4 way soil mix and I believe the mix may be compost, top soil and sand and may have bark dust or some other filler. Anyway, it is probably lighter than garden soil but if it has sand in it, I take that back as sand really heavy. Ideally, the bags would be filled with expensive bagged potting mix but who has that kind of money? If one makes their own compost, it could be mixed with some garden soil and the result would be lighter and pretty healthy. We re-cycle old potting mix and sift it and use the old stuff on the bottom half of a pot. We have the same goal of keeping the pots light enough to be able to move them. 20 gallons of garden soil almost needs forklift to move. By the way, we use larger pots (15 or 20 gallon) for dahlias because of watering issues. They hold enough water so that the plants only need one watering per day. And we use osmocote type fertilizer as it is too easy to burn dahlias in pots using granular garden fertilizer. One of the big downsides to potted dahlias is the daily watering. Your garden is watered much less frequently and with our drip tape it takes almost no effort.
HH Pink Martini has become much more popular in recent years.

calico20hill

Our solution for watering grow bags was to group them in a long line of clusters of 4 bags. We use the "Downward Sprinkler" from Dripworks...they are a little whirly springler-et that spins out a circle about 12" in diameter. Thus one sprinler placed in the middle of 4 bags will spin water into each bag. The downsprinklers can be placed anywhere along the drip-line. We watered about 74 growbags this way last year and it worked. I will use a better soil this year as last year's was too sandy and drained faster then I wanted. It was also a bit low in nutrients...our local sources idea of organic garden soil, which also introduced the new invaders, "Jumping worms". Our soil has been imported from Hillsboro, Oregon this time and looks very different, and passed the "Pea test".

Teddahlia

Another issue about grow bags is staking up the flowers. How do people do that? Some of the Hollyhill varieties may possibly be too tall. ☺

calico20hill

I wondered about that last year but those 15 gallon grow bags are so heavy nothing moved in the wind! I did line the grow bags up two by two with a mini sprinkler in the middle then a small gap before the next set of 4 on down the line. We put in the metal stakes at the 4 corners of the rectangle with twine around them just like for the raised beds, but I never saw any actually need it.

But I will do the same again, because those bags aren't moving...and the posts are still there.

JessieC

OK here are the results of my 2024 soil test. I added the numbers from last year's test where they differed significantly.
I'm disappointed that the pH has gone from 6.5 to 7.0. Anyone have ideas about that?
Last year, I had brand new soil that was high in almost everything. It was suggested that I test again after the season to see how things settled out. As advised, I did not add anything to the soil, but did do some foliar feeding from time to time, so I imagine that gets in there. I know one of them was a calcium supplement, but that value has gone down.
My plants did well in this soil last year. There were a few that were excessively bushy--too much foliage and very very few blooms. I wondered if there was some pocket of high nitrogen soil in that area. They were all together in a group--about 5 plants that had given me tons of flowers the previous year were gigantic leafy overgrown, and gave just a couple of blooms, if that.
Anyway, there's not a lot of time to make adjustments, but I would welcome any suggestions!
Thanks!!

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).

Teddahlia

Phosphorus is dangerously high so do not add more and do not add bone meal either. 6.5 pH is ideal for dahlias. 7.0 is a bit alkaline but that does help with the excess phosphorus. You only need to add nitrogen and do it evenly and not too much at one time. Organic material is high but not too high.

JessieC

Teddahlia thank you. I was hoping that the phosphorus would come down, but I know that takes many years. I’ve never added anything with P in it, and I’ll be cautious about any amendment. The soil came pre-loaded with extra P, and lucky that I had the soil test last year, as well as the collective wisdom of this group!
Is organic material a concern at this level?
Also, what are safe ways to add some nitrogen without it being a) too rapid, and b) combined with Phosphorus?

Flowernut

JessieC I always add a small amount of alfalfa meal to my planting hole. During the season, I use a soil drench for my plants when they are still small and a foliar spray for later on in the season. I make up my mixture using Organic Neptune Harvest brand fish fertilizer and seaweed plant food (2 separate products). My dahlias seem to like this mixture.

Teddahlia

In the old days nitrogen was in the form of nitrates . It is nearly all urea based now. Nitrates burn plants. Urea added in recommended amounts does not. It also takes a week or two activate as it is converted to nitrates by soil bacteria. Use the soil test data to calculate how much to add per 1.000- square feet and spread the amount over a couple of months. If in doubt about how to calculate it, a teaspoon of 46-0-0 urea per dahlia plant and watered in will get them growing well and is not too much. I use sulfur coted urea as it is a time release product and lasts for 6-8 weeks when applied. And it adds my needed sulfur too . I would add twice as much as it is time release. Organic gardeners rely on blood meal, chicken feather meal and sometime bat guano for nitrogen. Manures may have some nitrogen but are overloaded with phosphorus. Fertilizer is a very complicated subject and there are more myths out there than accurate information. AND THE ORGANIC MATERIAL IS OK EVEN IF A BIT TOO MUCH.

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!!

Teddahlia

As I read how people use various fertilizers and supplements and are organic or whatever I have noticed over the years, the ones who really, really grow the very best dahlias are the ones who do less fertilizer but more often. Most all of these exotic fish fertilizers and things like alfalfa meal or chicken feather meal or the strongest most powerful forms of chemical fertilizer work very well in small doses done often. Why does time release fertilizer work so well as it has the the same ingredients as the most powerful fertilizers? It is because plants want a little bit of fertilizer all the time, not all you can eat buffets once per month. I will always remember the fertilizer seminar done at Federation meeting where the very best exhibitors in the entire USA explained how they fertilized. The person who has proven to be the top show exhibitor of all, explained how she used cheap farm fertilizer in small doses and observed her plants carefully so she did not over fertilize or under fertilize. IF I WERE RICH and could use any fertilizer on the dahlias, I would either fertigate(fertilizer injected into the water in small amounts) and/or use the expensive osmocote type time release pellets., I would buy expensive equipment to measure the nitrogen in the dahlia leaves and have my crew with their pHDs keep track of the results of the fertilizer program. And a note on fish fertilizers and seaweed and such: Yes, they do have useful micro ingredients that your garden may be lacking. However, as with everything too much of a good thing is a bad thing and relying on these products as your main fertilizer year after year is probably not a good thing,

calico20hill

Teddahlia I have read your above article to the man who does the fertigation and watering system here. It was very useful. Thank you! Its always good when "the help" understands just what they are trying to accomplish!

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