peat free seedling compost

[David Pilling]

Another gardening season begins in the UK, and peat based compost is gone (legally the ban only starts in 2024). I was never a great fan of peat, but the replacements tend to be more expensive and unpleasant - bits of rubbish etc.

I'd like to know how to make my own seedling compost - there's nothing sadder than damping off - the now discontinued seedling compost I used never did that.

Metaldehyde is also banned - anyone like to suggest buying it for camping fuel and making ones own slug pellets.

I may now concrete over the garden. Make it harder guys, and see what happens.

[Diane Whitehead]

Fortunately we can still buy peat.  My rhododendrons and blueberries wouldn't be happy with coconut shells.

[David Pilling]

"It could never happen here" is another debate.

Today I saw sheep wool enhanced with bracken being sold for seedlings. Are they selling their rubbish or do they have any idea about seeds.

Neonicotinoids, Provado etc were banned by the EU. Emergency use as a seed treatment in the UK has just been approved to save the sugar beet industry from yellows virus.

[Martin Bohnet]

I have so much lime in my soil that rhododendrons  are completely pointless  - I can see when neighbors try, no matter how deep they exchange the soil. So for me my bog garden is the only excuse to use peat. at all. I'm actually quite happy with the wood based products, even though I tend to have a mushroom or two in a pot from time to time - alas, couldn't convince them to be something useful. I have my particular theories about biting into that second one. Theories I won't test.

So. senseless over-regulation, wasn't that the reason the UK left the EU. I see. At least it worked for the sugar beet industry. I mean, who needs those pesky bees when there is cheap sugar.

[David Pilling]

Martin - nice 'shrooms. 

[Steve Willson]

Hello, this is my first post to this forum, but it seems fairly user-friendly.  I thought I'd post this article I came upon regarding alternatives / supplements to peat-based composts.  This work seems to show that perlite is effectively a replacement in terms of water-retention capability and aeration capabilities.

[David Pilling]

Thanks Steve, that is interesting.

[kisaac]

I'd like to know how to make my own seedling compost

Hey, David...  Me too!  Although I live nearer the 'sustainable peat bogs' in Canada than you in the U.K., so I still use peat and/or coco coir as I wish, with absolutely NO GUILT!  Yes to sustainability, but- that coconut wasn't harvested from a happy palm growing in a natural jungle somewhere....      But, that's another post!

I actually contacted a big, international hippeastrum breeder/grower, and asked them for their Hipps seedling 'secret recipe,' and here it is!

Kindly see the below mix for starting hippeastrum seeds:
 
Only 2 ingredients.
1)  Buffered Coco Peat. (Coir)
2) Perlite
 
Ratio: 5 peat to 1 perlite.
Bark is not suitable for hippeastrum seeds as it decomposes and we also prefer to use a finer medium.

I tried it, and actually buffered my coir by soaking the coir in a 'cal-mag' solution in a big bucket. (A cool photo here of my seed flats of sprouting hipps in the 'buffered coco-coir / perlite mix.)


I don't have any testing options, so who knows if I did this right and if the buffering helped those little tikes grow bigger.  They sprouted and grew.  Somebody needs to test buffering the mix before seeding vs. fertilizing sprouted seeds carefully, skewed to add more Cal-mag, along with the N-P-K in home settings like we have.  And silica, which my store bought seed germination mixes now seem to contain.

This article on Potting Mixes for Certified Organic Production by a non-profit organization in the U.S. that says it is promoting 'sustainable' practices is actually one of the best I've seen, and gives you a rundown of the common ingredients and the 'secret recipes' in the appendix.  If you've heard about certain recipes for potting soil mixes, such as 'peat-lite,' that so many germination mixes are based on, they are listed with the person or organization who used it.  While somewhat specific in some cases to the U.S. (where we have cheap, sustainable peat from Canada)  and organic production.  I modify them to my needs, often replacing the peat component with coir.  In my area, we have several alternatives to perlite that I like much better.  One is local pumice, which doesn't bubble to the top of the pot as easily, and then blow away.  Local sourcing makes me feel better about some of my choices, as not wasting fossil fuels to ship  things around the world must be more eco-friendly, right?

About Coir:  It does dry quicker, so watch that!  This may or may not help with dampening off.  I've heard the sphagnum peat actually suppresses some fungus, but can't provide any proof of that.  Yes, I often find debris in mine (small plastic shreds, etc.) when I re-hydrate the block, and there are weed seeds that my store bought peat-based germination mix never has.  My coir source has a spec sheet that gives the salt content, and promises it is 'washed' to help remove the salt.  I don't check it, as I'm not using it for hydroponics.  I've heard of some coir being sold as buffered (not to be confused with rinsing to remove salts) but I have yet to find that.

And finally, if your post is to help us all practice using the new board, and not so much a discussion of peat alternatives for your seedlings; Hey! I've had fun learning about posting on my first post!  You can all answer now, to get your post count up!

[David Pilling]

Ken - thanks. I did want to know the answer, but an update... I am at the level of a DIY Superstore gardener (B&Q - diy.com). I've now had a load of their standard peat free compost, and it is OK, I think I can be happy with it. It is better than various less peaty composts of recent times, but it is twice the price of their previous peat based offerings. I do wonder what is in it, it is coarse, no sieving out the fine stuff for cheap seeds like with peat.

I'd been very happy with their peat based seedling compost, their new peat free seedling compost gets terrible reviews (hence my original post), despite this I bought a bag, so far it seems OK, looks to contain some sand.

At my level, stuff not damping off is success - I fantasise about picking up one of the microwave ovens people leave outside their homes, and using that to kill the bugs.

All that damping off was in peat compost, but not the special B&Q seedling mix which never had damping off problems.

I desperately do not want to open a debate about using peat. I believe the motivation for the UK ban is climate change.

[kisaac]

At my level, stuff not damping off is success - I fantasise about picking up one of the microwave ovens people leave outside their homes, and using that to kill the bugs.

I'm a DIY guy as well.  Early in my marriage (a lifetime ago?) I 'cooked' my home-made seedling mix in the oven to sterilize it.  It was explained to me that night, as our house still smelled of cooked dirt, that sterilizing my soils in our kitchen was not going to happen anymore...

I now 'solar sterilize' my bags of moist store-bought compost the best I can inside their bags or in my own clear poly or black bag on a hot day in the sun.  I'm not so worried about dampening-off, but these store-bought bags are pre-inoculated with fungus gnat larvae, which also can strain the best partner or room-mate arrangement.  Placing the bag on hot asphalt or inside a greenhouse helps, as would adding boiling water mid-way through. I have recorded temps inside that bag of 125 deg F (51 deg C) on a 80F day which, according to this link will take care of water molds, which is a step as water molds are one of the sources of dampening off.  I'd have to push it higher to 145F, the recommended  temp., to get more bad bugs, and probably assure an erradication of fungus gnat larvae, but I don't think the sun would get me there.  I then pre-moisten my seedling flats with boiling water, then let them drain 24 hrs before seeding.  I haven't worried about sterilizing my coir.

Temp at which the following are neutralized-  considering a twenty-minute time frame at this temp.

120F (49C)	watermolds (oomycetes)
145F (63C)	most plant pathogenic fungi, bacteria, and viruses, worms, slugs, centipedes

_{Source: http://phytosphere.com/soilphytophthora/soilsterilization.htm}

You need a much higher temp of 180F (82C) for weed seeds and 212F (100C) for 'heat resistant plant viruses and weed seeds,' but over 180F you risk creating soil toxicity.

to get all the living things, and to neutralize weed seeds. That article also says that at  145F (63C) you aren't disrupting the good bugs (colony forming soil bacteria and spores of various mycorrhizal fungi) that are helpful.  I've placed handfuls of mix in an aluminum fast food container and 'grilled it' in the BBQ grill when nobody was watching a few times- for 'mission critical' seeds that will be long-germinating in a very moist environment.

For those still reading, I would like to know how others do this stuff, as I know there are plenty of professional growers and educated people in the PBS!  I may be way off base.  I'm guessing that the new biofungicides will actually help, but they aren't yet fully university-proven or available, and VERY expensive.  I do know that the modern approach is now letting the bugs all live, in the hope that the good ones out-compete the bad ones.  Except the fungus gnats, of course...  So, maybe an inoculation with mycorrhizal fungi and a small fan blowing on those seedlings growing in compost from my compost bin is the future, after all?

~Ken, who is selfishly using this thread to practice his forum postings and decide what styles he likes best!

[Rdevries]

Why dont you just use sand and gravel and some sifted loam baked in the sun mixed and hydrated for a seed mix? 
Seeds seem to love to germinate in my gravel walks over sand and loam.

[ksayce]

My peat alternative has been to run decomposing woody chips through my shredder, then sift the fines to concentrate the humic materials. This lets me separate out the larger woody bits.  I grow mostly native species, and pots are held outside, so I skip the sterilization, thinking that mycelia are better for the seeds than sterile mix is.

[David Pilling]

Why dont you just ise sand a d gravel and some sifted loam baked in the sun mixed and hydrated for a seed mix? 
Seeds seem to love to germinate in my gravel walks over sand and loam.

Baking in the sun is a novel concept here in England. I used to germinate a lot of seeds in zip lock bags and eventually resorted to keeping the bugs at bay with household disinfectant ("Dettol" here,  Clorox?) I expect one could try sort of thing.

[Rick R.]

Some people use vermiculite.

Mostly, my seed starting mix starts with a good potting soil (with or without peat) and amended with perlite and/or grit to get the "right" consistency.  The potting soil is pasteurized, but other than that, I don't bother about sterility; I use dirty pots and even mix with old soil.  Damping off happens in perhaps one out of twenty seed lots, and I learn which to be careful of.  I grow a lot of alpines, and Townsendia spp. are one of them.  Rather than planting the seed in the soil, my fix is to plant the seed in a bed of #1 grit that is layered over the growing media.  Seedlings need to be bagged longer while they get a sufficient root-hold in the soil below, but it works like a charm for me. 

[Leo]

A stovetop pressure cooker running for 30 minutes at the higher pressure setting is the equivalent of a steam autoclave. The standalone electric units are not approved by the US Department of Agriculture for home canning, but the stovetop units are. I use my pressure cooker for sterilizing whatever needs it. Right now I am sterilizing some LECA for reuse with orchids.