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Will an uncooked, unlimed peat-based mix kill my seeds?

L

LogRhythmic

New member
I'm about to mix up some LCs mix to germinate seeds for my first grow. I have both peat and coco, as well as dolomitic lime, gypsum, and oyster shell flour. I'm concerned that:

1. The lime will need time to adjust the pH
2. If I use pure coco to avoid the need for a liming agent I will compromise the development of bacterial culture

Are these concerns valid? Thank you in advance for your guidance.
 
troutman

troutman

Seed Whore
Add a little dolomitic limestone to the peat and test the pH of the runoff.

If the pH doesn't go above pH 7 all will be fine.

Don't place the seeds until the pH is stable.
 
E

Easy7

Active member
Veteran
Cooking refers to microbe activity generating heat.

As far as ph it really depends on what you feed. The plant tolerates a wide spectrum of ph. 6.5 being ideal.

What real farmers do is apply manure that the bacteria and plants dump negative ions in the soil. Plants take up +ions and put in -ions. So they lime every so many years.

Don't go wild with the lime. The oyster shell will do a lot over time as will the lime. Mostly for calcium, then also buffer.

I don't lime my garden at all but sone will not hurt. I only use oyster shells at this point.
 
P

Pinnate

I use pre-fert peat with some washed sea sand and perlite added to open it up ─ unless you're extra careful, addition of lime can quickly shoot up pH to levels you don't want...
 
L

LogRhythmic

New member
Got it. I know the cooking is a separate process but I figured the microbes might do a little pH adjusting for me.

I'll go buy a pH kit, and probably go with mostly sterilized coco so I don't have to worry about it.

Thanks for the advice!
 
Ibechillin

Ibechillin

Masochist Educator
The lime goes to work immediately adjusting the ph. Powder form the calcium and magnesium are more easily available to the plant, pelleted needs time to break down. Gypsum is 100 times more water soluble than limestone and adds calcium as well as sulfur.

VerdantGreen said:
i recently halved my dolomite lime addition and added gypsum to make up the difference.

plants seemed to like it and i added a bit more this recycle.

VG
Click to expand...


VerdantGreen said:
hey Ulysses- im with you on the benefits of dolomite!

and the interests of getting this buffering/time thing nailed down I performed me a little experiment this morning. (slightly concerned that the 6 months thing may discourage folks from using it)

I took a glass of water and put a tiny shot of my citric acid solution into it .
I measured the pH with my pen and it read 5.1.

(YES, I am an organic grower with a pH pen, part of a rebel alliance of heads that like to know the acidity of their water, the pHorce is strong within us – deal with it! :nanana:)

I then took a half teaspoon of powdered dolomite lime and stirred it into the acidic water. Here is what happened to the pH :-
Original pH before addition of Dolomite = 5.1
1minute - pH had risen to 5.3
5 minutes – pH had risen to 5.8 – so within minutes we have a much more desirable pH plant-wise!
15 minutes – pH was 6.0 – doing its job nicely.
1 hr – pH was 6.3
2 hrs – pH is 6.4

ETA: 3 hrs - pH is 6.5
4hrs - pH is 6.6
5hrs - pH is 6.7
8hrs - pH is 6.9 - job pretty much done!

now I don’t claim that this experiment is mimicking the conditions in a pot perfectly, but I am very confident to conclude that powdered dolomite lime, well mixed into the soil, will do the job of buffering the pH of the soil possibly within minutes, certainly within hours of watering.

And bear in mind that the pH scale is logarithmic so a pH of 5 is many times more acidic than a pH of 6, and thus will react faster with the dolomite as can be seen in the experiment. As the pH gets nearer to 7 the buffering effect will slow down, but the pH is nearer what we desire anyway, and considering that the optimum availability pH for most macro and micro nutrients it between 6 and 7, the job that the dolomite is doing is, imo, exactly what we want from it.:joint:

Hope this helps. I’ll keep measuring throughout the day and update the results

May the pHorce be with you ;)
V.:abduct:
Click to expand...
 
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