Seedling Starter Mix

My plan for next year’s outdoor grow is to take all my unuseable plant material from this year, compost it, and mix it with Perlite to use as a seedling starter mix.
Has anyone done this? Benefits? Drawbacks?
Personally, I feel like a seedling mix comprised of nothing but composted cannabis material and Perlite would be a great mix but still want other opinions.

You don’t need any special soil or nutrients for germinating seeds. Doing so could actually damage your chances of a successful germination! The seed capsule contains all of the nutrients your baby girl needs in order to germinate. Over-nute-ing her could damage her genetics and thus messing with your growth or it could halt germination all together.
Consider sprouting her in coco. We’ve always had tremendous success that way. In the past when we’ve used soil mixes, composts, nutrients, etc., during our germination phase, it’s screwed our success rate and of those that did sprout, ended up having growth issues and reduced yield at the end.
Your babies have what they need for the first phase of their little lives - they don’t need anything extra from us until they’re about 1-2 weeks old (post-emergence).

But, quick question: do you pop your seeds directly into the soil or do you start them indoors and then plant after they’ve sprouted?

I realize that the seedlings have enough stored nutrients in the cotyledons to last the first few weeks, but composted hemp materials (that will be cut 50/50 w perlite) won’t have an overabundance of nutrients to begin with.
I’m thinking more about the possibility of beneficial microbes in the soil.
Typically, I start seeds in a wet paper towel and transfer to a starter mix but the method varies a little here and there, but I always start seeds indoors weeks before they’re planted outside.
And I’m not a huge fan of coco, considering the PH swing going from coco to soil.

Cotyledons don’t “contain” nutrients. Their purpose is to provide an immediate surface from which to begin photosynthesis. It’s the seed itself that has it’s little care package of yummies for her to get started.
Beneficial microbes are a great way to start! My favorite products, and the ones that have been most successful at our farm are: Mammoth, and Photosynthesis Plus by Microbe Life Hydroponics. Another amazing product for seedlings, clones and youngins’ is Clonex Clone Solution by Growth Technology, as well as their Clonex Mist.
Don’t get turned off by the product name. While it was originally formulated as a nutrient product for clones, it’s also excellent (and I really mean excellent) with seedlings! I included some product photos with the ingredients so you can make an informed decision.
I use the solution in conjuction with the foliar mist, being really deliberate about spraying the mist on the under side of the leaves as best as I can since that’s a site for major nutrient uptake.
One of my favorite microbial product is the Photosynthesis Plus. This stuff is LEGIT. You can use it as an addition to your watering and also as a foliar. I ran a side by side grow of two separate Super Silver Haze plants, ensuring to raise them identically except one received Photosynthesis Plus and the other didn’t. The difference was ridiculous. My girl who received P+ had stronger stems and branches, tighter node spacing, fatter buds, increased trichome coverage and was generally less sensitive to environmental changes. The other plant still did well, but there was a marked difference between the two. I also used P+ on a different plant as a foliar spray on an extremely sick plant - like, almost freaking dead - and I am convinced that using it in that manner is responsible for her recovery.
My most favorite microbial product is Mammoth. Mammoth was given to me to test a while back and, dayum. It’s not often that a product will actually impress me but this was no joke. Mammoth is real. Mammoth works by helping the plant to more efficiently utilize phosphorous. So important. I don’t exactly know the biochemistry of how it works but it “increases nutrient availability and plant nutrient uptake. Promotes plant growth and increases yields” - based on the description on the bottle. I don’t have a freaking full chemistry lab so I can’t say if that’s actually what happens, but what I do know is that the stuff works.
One time my supplier ran out of it and it was on back order for a while and my plants started having nutrient issues; poor stem and branch turgor, leaf yellowing, decreased bud density and overall became much more sensitive to environmental changes. Like, god forbid it got a few degrees warmer in the grow space, they’d freak out and throw cannabis hissy fits (getting slightly droopy, yellowing a bit, etc.)

I don’t mean to come across as an ad for any of these products. I have nothing to do with them and don’t have any relationship with the manufacturers. I certainly don’t receive compensation for using or praising them. I genuinely feel they are fantastic products and they’ve made a major positive impact on my grows.
Maybe they can benefit yours as well! The Clonex isn’t that expensive - it’s like $25 for a liter and lasts. The spray is more expensive at around $30 for a 100ml bottle. Photosynthesis Plus is like $25 for 32oz. Mammoth is not cheap. A 500 ml bottle is like $100 and a liter is like $200. The little 4oz sample size is $24. If you don’t want to commit to spending that much or getting a big bottle of any of these without being sure, they do offer sample sizes. I think you can buy or get a small sample size of each from your local hydroponics shop.

But to answer your first statement: I agree - a hemp compost should be A-OK. Great way to support your grow while recycling your trim!!

(sorry for rambling on for so long. just trying to help as much as possible.) :wink:

1 Like

I actually have all my nutrients and microbes already purchased, but that Photosynthesis+ does sound interesting.
I ordered Plant Probiotics. Has all the beneficial bacteria, fungus, humic & fulvic acids etc.

And this is the fertilizer

I also have Alaskan Fish Fertilizer and possibly a few other various ingredients to use for foliar sprays.

Ever notice that Mamoth P smells like an old dirty men’s urinal?

As for the original question. Sure you could compost all the old stuff, (as long as there were no mold/mildew issues), but honestly that stuff would be better to mix in your veg soil. You could, however, reuse your old soil if it’s been flushed. Seedlings need no nutrition. Just bland soil is all they need for the first couple weeks.


@Drinkslinger YUP. The only thing that stinks more than Mammoth is the Photosynthesis Plus I mentioned. Holy shit.
It takes your breath away. It’s like a dog fart that never goes away but it’s incredibly effective.


Safer fungicide smalls pretty bad too. Like someone vomited in a pile of manure.
It stinks up the whole house. :-1:


Be careful with foliar sprays. Foliars are tricky mistresses and can legit destroy a plant. You reeeeeealllyyy don’t need anything at the very beginning. You don’t want to stress and overwhelm your baby girls. Really in the beginning all they need from you is a moist paper towel to germinate, a basic plain medium to establish, good light, minimal water and privacy. The baby girls don’t like or need to be fussed with or fed a fancy menu of delectables and could do all kinds of weird things, including die.
BUT once your lil’ gals are established and have a few fan leaf complexes then those microbials look like good stuff.
When we treat our ladies well they ALWAYS treat us well in return. :slight_smile:


Ha! Yea there’s nothing worse than a really great product that you absolutely need and therefore are forced to gag all damn day because of some liquid shit putrifying in the air. Lol


@Drinkslinger There won’t be enough to do any good for a garden, so I figured I’d use it for this lol
@the2409labs I don’t plan on using foliar sprays or fertilizers til they are a few weeks old.

I did some research on Photosynthesis+ and you got me sold haha Thanks for the info!

1 Like

Super happy to help!! Just don’t be surprised when you smell it. It’s REAL. lol. But it’s truly incredible. :slight_smile: happy growing! Reach out if you need anything!

1 Like