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Doobie Brother

Can one use too much compost ?

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Here's a weird question: is it possible to over-do organic ingredients such as composts, guano etc. ? My gut tells me it's hard to overdose this way, but I would like confirmation from the experts here.

Cheers

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It's a little harder to overdo it with compost, but one can easily use too much guano and several other ingredients. Guano and blood meal are two of the easiest to overdose. One can fairly easily overdo it with molasses, too. Fish ferts and chicken litter are two more amendments that come to mind...In fact, moderation should be used with all amendments. grin

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Moderation is my middle name! D.M.Brother smile

Blood meal; wouldn't that be a little harder to over-dose with, unless it were liquid ? With molasses, are you referring to overfeeding the micro-herd ? Lastly, why is fish considered to be on that list GB ? I'm asking because I don't know, not because I'm being a wise-ass (for a change) smile

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Blood meal is easy to overdose on. I use small amounts of blood meal and other organic items that contain nitrogen . Composted alfalfa works good but you can

Also use to much if you are not careful.

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Blood meal is one of the easiest amendments to overdose. At 12% nitrogen, a little goes a long way. Yes, Doobie, I was referring to overfeeding the micro-herd with molasses. This looks like nitrogen deficiency, as the population explosion eats up all of the available nitrogen in the soil at a rapid pace. I put fish ferts on the list because it is also high in nitrogen.

I know that everyone looks at higher numbers for NPK ratings, but reality is that when using high NPK ratings, you should use much smaller amounts. Cannabis grows great on a relatively low NPK rated soil mix.

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You've raised a few good points GBuds, firstly that people tend to believe that 10-10-10 is somehow better than 1-1-1, and secondly that cannabis prefers smaller amounts of food. The only thing I can add is to keep that small amount of food coming, ie. a constant source is better than intermediate blasts.

Thanks for the posts guys.

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Yes you sure can doobs, like others say its rich in nutrients, but theres also the other factors. You caan create an anaerobic presence in the medium, encourage too much water retention and so forth. Its hard, but not as hard as you think to come across this situation.

Generally as a rule, if your having troubles with a medium the answer is generally add compost, but like anything, too much of one thing can be a bad thing..

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Simo, how would an anaerobic situation be created by over-use of compost ? I suppose if you add enough to overwhelm the normal properties of the grow media, i.e make it less porous and therefore it holds more water, then yes, it's possible.

Hmm...what ratios of compost to media do you guys use ? I've been slowly increasing the compost ratio, adding a little more each timme. I'm up to roughly 1 part compost to 2 parts everything else.

For clarities sake, I'm using commercially produced composts - sheep, cow, and 'ocean' composts, in a blend of all three.

Thanks for reading.

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Just adding my $0.05...

I don't grow purely organically, but I do add my own compost to the organic potting mix I buy (which is mostly peat moss and composted bark, some perlite).

My compost is derived from mostly weeds I've pulled from the garden, some lawn clippings, various yard trimmings, and some kitchen waste (vegetable scraps). The weeds have roots and the roots hold onto some soil, so my compost also adds some sand/pebbles to the mix.

Now, this compost is really rich and dark and thick, I add about 1 part of it to 3 parts of that potting soil, and all seems to be good. Any thicker than that, or if I don't stir it all up well, and yeah, it takes on a sort of impenetrable soggy nature, which being rich in organic matter with lots of microbes feeding on it and no gaps to let air in, is going to be low in oxygen.

Hard to describe what happens... a too thick mixture, even if I fluff it up a lot and don't press it down much, it just sort of collapses in the pot like a bad souffle and becomes thick as clay. No "spring" or "bounce" to it at all.

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Organic is slow to break down, if its breaking down slower than your adding it, combined with water retention it can create a barrier level of sticky decomposing matter. Same thing with compost piles, you have to turn them or you see how the inside of the pile looks and its not really feasible to turn the soil in your pot with a plant growing in there.

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Ha Simo, no probs smile

So the anaerobic thing is more of a ... mixing problem. If you add 1 part compost to 2 or more parts of media, say Progro, it would be a great idea to increase the perlite content, to ensure all that thick compost is well blended with lots of solid bits such as perlite, coir or vermiculite.

You know, when I started this thread my thought were focused on adding too much of a good thing - over feeding, and not so much on creating an airless mess with too little aeration.

Live and Lurn!! wink

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Yeah of course, you can still OD on the nutrients, but as you begin to add too much organic matter (as with everything) chances of running into any sort of problem becomes greater.

I know you do the research tho, so i wouldnt be overly worried, but a good suggestion might be to mix up the organic matterials you use, i.e rotation of what goes into the pots, different products and so forth

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I do that now Simo: I note what each pot gets, how much, that sort of thing, in my grow log. So far I've not seen any real advantage to using a particular flavour of compost, e.g. bovine, avian, etc.

This is why I've started to mix a few together, to cover all possible bases smile

Organic growing is still a new method for me, and I have a LOT yet to discover. Thanks guys for the advice and tips, it's great that we have a good crew of experienced growers here to help out.

Cheers

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Here's a weird question: is it possible to over-do organic ingredients such as composts, guano etc. ? My gut tells me it's hard to overdose this way, but I would like confirmation from the experts here.

Cheers

Well for starters there is a difference between compost which is usually considered a soil amendment and guano which is technically an organic fertilizer as it contains at least 5% in either N, P, or K. Compost in general tends to have low NPK, but that does not mean it lacks enough N, P or K to effectively grow a plant. So while you can easily apply too much guano with ill effects, there is no such thing as too much compost as it is lower in the big three NPK, with a more "balanced" nutrient profile. You could grow AMAZING plants in pure compost; that was made using a diversity of input materials and add nothing but rock dusts like Gaia Green Glacial Rock Dust or Azomite to gurantee a complete nutrient profile. If you can get ahold of it I would also HIGHLY RECOMMEND Zeolite. It is a hexagonal shaped clay particle with excellent water/air retaining properties as well as helping increase the total Cation Exchange sites (nutrient holding capacity) in your soil.

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Thanks for the tip on Zeolite PH, but I live near the edge of nowhere...lucky to be able to get my hands on Perlite! If and when I get to a real city I'll try to scrounge some up.

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Thanks for the tip on Zeolite PH, but I live near the edge of nowhere...lucky to be able to get my hands on Perlite! If and when I get to a real city I'll try to scrounge some up.

I would opt for vermiculite over perlite when possible. It helps lighten up heavy potting soils adding aeration but it also retains water MUCH more efficiently then perlite. Vermiculite will also have some Cation Exchange Sites on it as well so it will retain some nutrients as well. I would also highly recommend not using Dolomite Lime (especially not Horticultural Lime which is not permitted in organic cultivation) as they have the improper Mg to Ca ratio, having far too much Mg in it. If you can get it id recommend just using straight pure limestone or ground/crushed oyster shell or even crushed eggshell (smaller the particle size the better/faster acting it will be) which is almost pure Ca. I would opt for the oyster shell/eggshell options first if possible. Don't go overboard on adding limestone (especially not Dolomite Lime! etc) Ca sources either as Ca is high up on the Cation Exchange hierarchy and will displace other nutrients which will leach out of the soil, flooding it with lots of calcium but you will see deficiencies in other nutrients. This of course will not effect nutrients held up in organic matter(which includes nutrients held inside living microbes) that is being broken down by microbes, this will only effect the cation exchange sites on the clay, sand and silt particles.

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Fwiw PH, I use crushed egg shells, no dolomite, and prefer Perlite as it does not hold as much water as vermiculite. I (usually) don't want that much moisture in my pots over time, that is, I'm leery of root rot issues that I imagine are possible with vermiculite.

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Fwiw PH, I use crushed egg shells, no dolomite, and prefer Perlite as it does not hold as much water as vermiculite. I (usually) don't want that much moisture in my pots over time, that is, I'm leery of root rot issues that I imagine are possible with vermiculite.

Personally from my own experience, and from what I am learning in post secondary for horticulture, I have discovered vermiculite to actually be superior to perlite for lightening up potting mixes and increasing air retention in the potting mixes. The reason I don't like perlite as much anymore is I always found it much easier to compact and it breaks apart into smaller pieces much more quickly then vermiculite well, which also means it is more likely to over compact, especially if you are moving your pots around a lot which will naturally cause mild compaction each time you lift up and set down the pot. Unless of course you do it ULTRA gently. The other added benefit with vermiculite is you will not have to water the pots as often as it retains more moisture then perlite will (has to do with the structure and physical properties) as well as increase air retention. So long as you keep adding more compost top dressing or compost tea and keep a healthy microbial population then you should have few problems with over watering. It is really hard to over water potted plants so long as the potting mix does not contain a ton of peat, leaf mould and/or clay particles. If you find you are having problems with root rot try adding a vermiculite/sand mixture, I find this will greatly improve drainage without a huge effect on water retention vs the stereotypical peat + perlite based potting mixes. Even though the perlite will help with drainage it will not produce as optimal of performance unless growing plants that like their roots to stay wet, like bog plants such as blueberries. The "ideal" soil will be 40% sand 40% silt and 20% clay, not including organic matter.

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Ive grown in nothing but pearlite for decades in my drip systems. It works great. End of crop. it's thrown away. laugh

That seems a little wasteful to just throw it away, why not just rinse and reuse the perlite?

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the roots grow so deeply into the pearlite, its just a solid mass of roots with grains of crushed(by the root action) pearlite.

It's 3 bux a crop, not really cost prohibitive.

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the roots grow so deeply into the pearlite, its just a solid mass of roots with grains of crushed(by the root action) pearlite.

It's 3 bux a crop, not really cost prohibitive.

Ever try using sand and landscape fabric to hold the sand in? The sand could easily be washed away from the root mass.

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