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fertilizer When to fertilize potting soil?

Edmick said:
With all due respect solid7 i kind of disagree. A plant WILL take up more nutrient if its there. How else would you explain nutrient burn? A plant will take everything its given. Good or bad.
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Nutrient burn is not a function of uptake, it's a chemical reaction.  Also referred to as "Osmotic shock".  It is most common with nitrogen, and almost, if not totally, exclusive to inorganic nitrogen sources. (salt-based)
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Plants don't binge like people and animals do. This is one of the hugest myths ever propagated in garden culture.
 
Nutrient burn is a result of too much salt - nothing to do with nutrients
Plants take up nutrients not by diffusion or osmosis but cation exchange
 
Root hairs pump hydrogen ions (H+) into the soil through proton pumps. These hydrogen ions displace cations attached to negatively charged soil particles so that the cations are available for uptake by the root
If the plant doesn't need nutrients then it simply stops pumping ions
 
Nutrient burn happens from osmosis where too much salt draws moisture of of the plant
 
Which is also why stuff like mushroom compost, fish emulsion, worm castings etc don't often cause nutrient burn because there isn't a large amount of salt in them
The nutrients just stay in the soil until the plant needs them 
 
Powelly said:
Nutrient burn is a result of too much salt - nothing to do with nutrients
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No, not nutrients, per se, but a very specific nutrient - nitrogen.  Specifically from inorganic sources. (salts) But for the reason you mentioned, which is the salt index. (osmotic shock is when salts draw water out of the cell walls in the roots, and leads to dessication)
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My apologies if you were answering the OP, and not me. Otherwise, hopefully I clarified the intent of my last post.
 
The answer you gave was close enough for all intents and purposes
I'm sure someone that knows more about biochemistry can slam down on what I said as well
 
But for all intents and purposes it's correct and illustrates that it's not fertiliser that causes the "burn" it's a salt level too high and that a plant will only take up nutrients if it requires them
 
The interesting part of this story is why overdosing certain nutrients causes different symptoms to other nutrients
I suspect that plants are unable to preferentially absorb one nutrient over another - I've not read into this though so it's just a guess that "seems right"
 
Powelly said:
The interesting part of this story is why overdosing certain nutrients causes different symptoms to other nutrients
I suspect that plants are unable to preferentially absorb one nutrient over another - I've not read into this though so it's just a guess that "seems right"
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The concept that you are looking for, is called "stoichiometry".
 
https://en.wikipedia.org/wiki/Stoichiometry
 
A nice, scholarly article on the subject:
 
http://onlinelibrary.wiley.com/store/10.1890/ES15-00451.1/asset/ecs22015612273.pdf?v=1&t=j0g257jf&s=541bec6314602e33807b1722cf63fe230b06c7de
 
Very interesting. I love the science behind it. You guys are awesome. Thanks for all the advice.
 
So i guess my next question now that I'm using the earth juice is what strength should i be watering with? On the bottle it has directions for "mild", "medium" and "strong". I know this may be difficult to answer due to different variables but where should i start?
 
When i first started growing i always just used miracle grow or whatever crap they had at walmart but due to the sharp rise in popularity of marijuana cultivation (i live in southern california by the way) there seems to be a hydroponics shop on every corner so im blessed to have unlimited options for gardening supplies and fertilizers. I'm just now starting to experiment with different fertilizers and soils so i appreciate everyones input immensely.
 
If you have hydro shops everywhere, then I'll give you my preference for inorganic fertilizers - DynaGro Foliage Pro, or CNS17 Grow.  Both 1 part formulas, both grow peppers all year round, with nothing else needed.  If your water is anything over 7.5 ph, you probably won't even have to buffer either one of them.
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But like I said earlier, the Alaska Fish and Alaska seaweed is incredible for the money. 
 
http://www.homedepot.com/p/Alaska-1-Gal-5-1-1-Fish-Fertilizer-100099249/100211859
http://www.homedepot.com/p/Alaska-Pennington-32-oz-Pure-Kelp-Plant-Food-100523611/203143792
 
solid7 said:
I'll give you my preference for inorganic fertilizers - DynaGro Foliage Pro
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+1 for DynaGro products. It's all I use since I grow in 5:1:1 mix in containers. That stuff is great. I start the season out using their "Foliage Pro" (9-3-6) blend. Mid-season, when pods start setting, I switch to their "Bloom" (3-12-6) blend. I'm not sure if the Bloom stuff actually works any different than the Foliage Pro, but it's the same price, so... I've never tried the Foliage Pro throughout a full season

Anyway, here's some "proof in the pudding." These are my plants last year, probably around September-ish:


I probably got close to 10 harvests, almost all this size too


One thing I will mention about DynaGro though; and this ONLY happened to me last year (2016)- on BOTH the Foliage Pro and the Bloom formulas in the gallon jugs they came in. Huge calcium deposits built up in the bottom of the jugs, still not sure why. Never happened the 3 or 4 years before that I've used their products


Not sure why it happened. It wasn't stored in "extreme" conditions or anything. Kept it in my garage all Summer. In the shade, in New England (70*s F maybe?). My plants didn't complain, and it won't deter me from using their products again this year. Just thought I'd share.

YMMV :)
 
Those calcium deposits are why most fertilizers don't incorporate complete calcium.  It's very hard to have calcium in the same solution with other nutrients and minerals, due to the tendency for calcium to bind itself to them. 
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I've not seen this happen with the CNS17.  But in fairness, I've not stored it long term, either.  This ability to stay unbound in solution is supposed to be one of the big breakthroughs for the CNS17.
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I'd be interested to see you grow your plants out full season, in side-by-side comparison with the "bloom" formula, vs solely the "grow", and report the results.  I know what the results are, but it would be great to have my own results validated.
 
MikeUSMC said:
+1 for DynaGro products. It's all I use since I grow in 5:1:1 mix in containers. That stuff is great. I start the season out using their "Foliage Pro" (9-3-6) blend. Mid-season, when pods start setting, I switch to their "Bloom" (3-12-6) blend. I'm not sure if the Bloom stuff actually works any different than the Foliage Pro, but it's the same price, so... I've never tried the Foliage Pro throughout a full season

Anyway, here's some "proof in the pudding." These are my plants last year, probably around September-ish:


I probably got close to 10 harvests, almost all this size too


One thing I will mention about DynaGro though; and this ONLY happened to me last year (2016)- on BOTH the Foliage Pro and the Bloom formulas in the gallon jugs they came in. Huge calcium deposits built up in the bottom of the jugs, still not sure why. Never happened the 3 or 4 years before that I've used their products


Not sure why it happened. It wasn't stored in "extreme" conditions or anything. Kept it in my garage all Summer. In the shade, in New England (70*s F maybe?). My plants didn't complain, and it won't deter me from using their products again this year. Just thought I'd share.

YMMV :)
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Can you give us more info on your fertilization schedule? How much and how often?
 
solid7 said:
It's very hard to have calcium in the same solution with other nutrients and minerals, due to the tendency for calcium to bind itself to them. .I've not seen this happen with the CNS17
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That actually makes a lot of sense, solid7. I've never heard of CNS17; I'll have to check it out. Thank you

mas_fuego said:
Can you give us more info on your fertilization schedule? How much and how often?
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Nothing special, mas_fuego. I don't start using it until they're in 1 gallon pots, at 1/2 teaspoon per gallon, once a week. Once they're in 5 gallon buckets, I use 1 full teaspoon per gallon, once a week.

These pics are from 2015. All pics taken were roughly 10 days apart, right after going half strength (1/2 tsp/gal) with the Foliage Pro


 
MikeUSMC said:
That actually makes a lot of sense, solid7. I've never heard of CNS17; I'll have to check it out. Thank you

Nothing special, mas_fuego. I don't start using it until they're in 1 gallon pots, at 1/2 teaspoon per gallon, once a week. Once they're in 5 gallon buckets, I use 1 full teaspoon per gallon, once a week.

These pics are from 2015. All pics taken were roughly 10 days apart, right after going half strength (1/2 tsp/gal) with the Foliage Pro


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How much of the gallon do you put on each plant?

That's the part I can never figure out.
 
How much of the gallon do you put on each plant?

That's the part I can never figure out.
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In general, when you water in nutrients, you want about 10-20% of whatever you pour in, to run off. (once you've reached the point of saturation)
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Because different media have different properties, and wet at different rates, that's just a guideline. Make the plants fully wet, is a better answer.
 
Edmick said:
With all due respect solid7 i kind of disagree. A plant WILL take up more nutrient if its there. How else would you explain nutrient burn? A plant will take everything its given. Good or bad.
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nutrient burn is because of lock up, the plant can't do its thing because of "a clog in the system", to use a metaphor.  Plants can not use more anything than its metabolism allows.
 
U)<now said:
Which Espoma fert do you use?
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They're really all almost the same but I like garden-tone for my starts and that or tomato-tone later on.  The biggest benefit I see to using espoma is that they're inoculated with beneficial bacteria.  Just to reiterate i use a small amount for my starts then feed when planting out and halfway through the season.  I have top dressed potted plants with it and had success but without the soil life to make it bio-available I think liquid ferts are better for pots. 
 
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