Best medium for starting seeds

zaphod42February 22, 2014

In a previous thread I was advised to use a seed starting medium that wasn't primarily composed of peat. Since then I've been casually looking at the seed starting mixes at Home Depot, Steins, etc. Everything I've run across so far is 60-90% peat. Any recommendations for brands that aren't primarily peat? I'm not starting a whole ton so don't want to blend my own or have to buy a gigantic bag. Thanks!

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I have always used - successfully- the brand name peat based seed starting mixes. I prefer the Jiffy. What is important, is to transplant into a courser mix after you have a set or two of true leaves.

If you want a courser mix to start with (better for some of the more particular slow growing plants) just get a small bag of Pearlite and mix in 25-30% pearlite.

    Bookmark   February 22, 2014 at 3:38PM
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tapla (mid-MI z5b-6a)

You'll get lots of suggestions with explanations at the Container Gardening Forum. Look for one thread that's active now about seed starting in calcined DE.


    Bookmark   February 22, 2014 at 3:48PM
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I understand that there may be hazards to using diatomaceous earth. Rather than worry about that, I use Premier Pro-Mix BX, which is peat-moss based, but contains other ingredients. It can be a little coarse, so I hand shred it a bit. I get mine in a compressed bale, so the hand shredding is needed anyway.

When working with anything that can be a bit dusty, it is a good idea to wear a face mask -- it's not a good idea to breathe in anything but clean air. I use a paper mask even when working with dry peat-moss-based products, as well as vermiculite or perlite. And I wet those products in the bag to hold down any dusting. I don't plan to use diatomaceous earth any time soon.


    Bookmark   February 22, 2014 at 5:59PM
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ken_adrian Adrian MI cold Z5

a seed startring mix.. is ground very fine .... so the seeds can pop out ...

as compared to a mix.. that has big chunks in it ...

i am a cheapwad ... so i dont want to go buying two bags of mix...

so use your courser mix .... but dont bury the seeds very much.. if at all ...

since you dont mention what seed you are starting.. we cant even be sure that any of them need to be buried at all ...

anyway ... take out a gob... i would put it into a dollar store turkey pan ... moisten it up ... and then put it into whatever you are starting your seeds in ...

and then top it off with a sixteenth of an inch of dry ... if any of the seeds need dark ... or use the moist.. just dont pack it down ... thats probably the trick.. light and fluffy ... and not much on top ...

then when you get to the first true leaf stage.. up-pot them into the regular media ... at this stage i prefer 6 oz solo cups ... if you have the space to spread them out ....

media is all about water management .... as not much stuff like sitting .. sopping wet ... so the chunkier your mix.. the better the water flows thru.. and right out the bottom.. if you tend to overwater ...

if you were doing a whole greenhouse.. i think media would be important...

but when you are just doing a few things.. i wouldnt worry about it all too much ...

the odds of your media killing things is low to nil.. as i am sure you can find other ways to kill them.. lol.. I DID!!!! [mostly forgetting about them for a week or two.. lol]


ps: you could put the course stuff thru a strainer... and work out some of the bigger chunks.. if you wanted to experiment ...

    Bookmark   February 22, 2014 at 6:10PM
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Hi Ken,

I have thought about putting the Premier Pro-Mix through something like a meat grinder to break it up some, as an alternative to manual shredding. But we don't have a meat grinder. I should probably be on the lookout for one at the next garage sale I am at. I don't think people actually grind their own meat nowadays.


    Bookmark   February 23, 2014 at 12:45AM
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floral_uk z.8/9 SW UK

Can you get coir or other mixes? Peat is used less and less here and widely discouraged. This article is helpful in explaining how to adapt multi purpose mixes for seed starting. (nb the word 'compost' is used in the UK to refer to mixes/media as well as broken down organic matter.)

Here is a link that might be useful: Adapting mixes

    Bookmark   February 23, 2014 at 6:46AM
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tapla (mid-MI z5b-6a)

Coir has inherent issues growers should be aware of. It has an extremely high K content, less loft than peat - which means it should be watered from the bottom or via mist, a high pH - which precludes the use of dolomite as a liming agent, and it's often very high in salinity - which could spell trouble for seedlings by compromising their ability to take up water and nutrients.

I'm not sure why people have the idea seeds need to be started in a mixture comprised of very fine material. They don't. I make 2 different soils, both of them very coarse and chunky when compared to most off the shelf growing mixes. I sprinkle seeds on top of the mix, then cover them with fine peat to about 1/8 to 1/4", water as required to keep the top hydrated (using a spritzer or one of Dramm's Fogg-it nozzles. I get what I figure is the same germination rate as in seed starting mixes at a fraction of the cost and never lose seedlings after they've sprouted, so what's not to like?


This post was edited by tapla on Mon, Feb 24, 14 at 10:03

    Bookmark   February 23, 2014 at 10:53AM
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No, you don't want ALL peat, but a 60 to 70% mixture should be fine. Peat provides a good base for starting seeds in, as opposed to regular garden soil, which may be clay or all sand...or whatever. Anyway, if you want something with a little "less" peat, then mix some perlite in with it.

The easiest way? Buy an organic seeding mix. You will have fewer issues with unwanted organisms etc., and you don't have to mix your own and you can buy it in a smaller bag.

Here's a good explanation of all of your options for choosing Growing Medium.

Here is a link that might be useful: Stuff to grow stuff in

    Bookmark   February 24, 2014 at 11:34AM
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tapla (mid-MI z5b-6a)

There are 2 ways to look at growing. One is from the plant's perspective and the other from the grower's. Most often, the perspectives are at odds. The grower wants what's best for the grower - what's easiest, the plant wants what's best for the plant, which is seldom what's easiest.

Neither perspective is right or wrong, but there is a decision to make. Mixes with 60-70% small particulates, like peat and compost, are going to hold a LOT of excess water and carry the threat of seedlings dying soon after germination from one of the damping off diseases if not watered very carefully; and the shallower the container the seeds are started in, the more likely the issue is to be made manifest.


    Bookmark   February 24, 2014 at 1:13PM
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rhizo_1 (North AL) zone 7

I've always filled my shallow germination flat with my usual coarse potting medium, then sift a dusting of dry peat on top. A quick misting will dampen it before I sow my rows of seed. If some of the varieties require dark in order to germinate, I sift another layer on top, mist with water, wait for the magic.

I've always considered those very fine germination mixes unnecessary at the very least but the cause of lots of problems for most.

    Bookmark   February 25, 2014 at 6:10AM
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samhain10(5a - MI)

I'm not sure what the complaint is about peat, other than the hazards of breathing in particulate matter. Zenman addresses that with saying to wear a mask - or a kerchief tied around the face, I'll add. I was under the impression from something I read a long time back that peat actually had some properties that inhibited the bacteria that cause damp-off. Don't know if this is true.
Anyway, I used to use Sunshine Mix which is primarily a peat mix with perlite added, and depending on which mix, fertilizer or not. Can't get it now for a price I can afford, so I'm now using Baccto Propagation Mix - also peat based with perlite added, and limed to a pH of 6.5 or so. It's in a 2 cubic ft bag, but I think it can be had in smaller quantities.
I have tried a variety of different mixes, even mixing my own using peat, vermiculite and perlite. I have to say that I have always had best success with the less coarse, light and airy mixes like the peat/perlite mixes.

    Bookmark   February 25, 2014 at 10:07AM
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tapla (mid-MI z5b-6a)

I spend a lot of time on forums related to growing in containers, like Houseplants, Container Gardening ....., and most of the problems that people come to the forums seeking remedial help for are directly related to growing in soils that are comprised primarily of fine particulates - like peat, compost, composted forest products, coir, sand, topsoil; this, because of the effects of excess water retention in fine soils and its effect on root health and root function. Even most cases of disease and insect infestation result from poor vitality and a depressed metabolism resulting from too much water and not enough air in the rhizosphere (root zone).

A healthy plant is impossible w/o a healthy root system.


    Bookmark   February 25, 2014 at 3:33PM
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samhain10(5a - MI)

Tapla - Ah, I see. Yes, some of those peat mixes are heavy like that, I agree. I haven't had that problem with the two propagation mixes I mentioned, perhaps because of the addition of perlite, which aids drainage.

    Bookmark   February 25, 2014 at 7:55PM
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runswithscissors(MT 4/5)

One thing I didn't see the "Magic Bullet" in my seed starting mix.

Worm Castings!!!

My success rate went from about 35% to 99% just by adding this to my mix. It has some sort of natural property in it that wards off the damping-off-disease. Plus it has a teeny amount of nitrogen in it and as soon as a new sprout emerges, it just takes off. I get mine from Wriggle Worm...but I suppose all worm poop is the same. I will never grow without it again.

Also, since I know myself, as kind of an OCD waterer (I can't stand it if the top of the soil doesn't look moist) I add extra perlite to my mixes too, and this allows me to water more than is required without drowning my babies.

By adding these two extra ingredients, I have gotten away with buying the cheap store potting mixes and everything seems to be thriving for me so far this year.

Last year I tried the coir-route and didn't really like it. It holds too much water which encouraged algea and fungus gnats like crazy (and damping-off). And sprouts seemed to have a hard time extracting nutrients and seemed yellow and weak unless I transplanted them into regular peat based potting mix.

    Bookmark   March 5, 2014 at 5:16PM
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