Best medium for starting seeds

10 years ago

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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Comments (14)

mandolls
10 years ago
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.
tapla (mid-Michigan, USDA z5b-6a)
10 years ago
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.

Al
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Best medium for starting seeds
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Hi zaphod, " Everything I've run across so far is 60-90% peat. Any recommendations for brands that aren't primarily peat? " I wouldn't call 60% peat primarily peat. I would call 90% peat primarily peat. Is your objection to peat that it is too water retentive ? You can always reduce the water retentiveness of a mix by adding extra Horticultural Perlite. (Hoffman's or Miracle-Gro are good brands of it.) Don't use a non-horticultural grade of Perlite, because it could have a lot of fines and present a dust hazard. Perlite chunks retain air and don't become waterlogged. Vermiculite, on the other hand, does retain water, so, in that regard, Vermiculite functions the same as Peat. Also be sure to use a horticultural grade Vermiculite for safety. Some industrial grades could be hazardous to handle. I use Premier Pro-Mix BX, which already has added some Perlite and Limestone (for calcium nutrition and pH adjustment). I usually add some extra Perlite to my Pro-Mix. I frequently cover my seeds with Country Cottage Horticultural Vermiculite because it is fine-grained, retains water well, and yet the seedlings have no difficulty pushing up through it. If you wanted to exclude Peat altogether (some people object to depleting the natural supply of a resource beyond its renewable rate), you could formulate your own mix using just horticultural Perlite and horticultural Vermiculite. I would start off at about 2/3 Vermiculite and 1/3 Perlite. If you are really concerned about good drainage, you could go 50-50 on the formula. Small seeds (for example, non-pelleted petunia seeds), could fall down too deep in a coarse mix. To prevent that, I would include a thin layer of non-additive toilet tissue below the seeds, to keep them in place without interfering with their root growth. There are some people who favor tree bark as an ingredient in growing mixes, and some commercial mixes contain a significant amount of it. ZM (not associated with any product or vendor mentioned)
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Lots of good comments & advice already given (notably by Fusion, Digdirt & Plantatus) to which I concur. I'll just try to add my 2 c's on a few points already discussed. "Sterilized compost is nothing like seed starting mix. As explained at least a couple of times above seed starting mix is composed of peat from peat bogs. The amount varies but is usually 60-80%. To that either perlite or vermiculite and a little lime is added. Then some sort of nutrient supplement is added to some, but not all, of the mixes." A commercial mix has been sold here whose main component is shredded bark; I've used it for several years, and am happy with the results. It would offer a good alternative for those who consider the use of peat to be the destruction of a non-renewable resource. "I still say I don't understand how some of the experts can jive their zeal against uber-big businesses having their fingers in seed companies, promote heirlooms and sustainability, talk about preparedness and self-sufficiency in the "just-in-case-it-all-comes-crashing-down" world and at the same time proclaim that nothing other than store-bought seed starting mix will work. At all. Ever." As I've read through this thread, that wasn't what I heard. What has been said is that you should start with a sterile medium... and provided that you sterilize a fertile soil or mix, the results can even be better than the sterile (but nutritionally weak) seed starting mixes sold commercially. Really, all of the other discussions - indoor versus outdoor, etc. - take a back seat to that issue. Fusion's experience with his own mix was a great example of what can be accomplished, and leaves the door open for a great deal of experimentation. Those who grow their crops in subsistence levels - and rely on them for sustenance - can't afford the chance of a complete loss before the plants even get in the ground. You try to minimize the risk to the greatest degree possible... and at present, the sterile mixes sold commercially are a very reliable way to do so. If those were not available, however, I think the people in question (self among them) would find alternatives - some of which have already been mentioned. My methods (in my climate) would likely differ from those in warmer zones. And if "it-all-comes-crashing-down", there would not only be no starter mix, but no power for lights or bottom heat. At that point, IMO, seed starting becomes something of a non-issue... I would be less concerned with forcing hot-weather plants (of relatively low nutritional value) to grow in my climate, and more concerned with growing nutrient-dense grains & root crops that don't require coddling to produce. "This is something I do [sterilizing containers], even though I always kind of wonder what the point is when I don't bother to sterilize the seed starting mixture. But it just seems to make good sense." Even when you start with sterile soil & containers, contamination can (and often does) occur through airborne spores; fans & dusty or damp locations can increase the chances of initial infection. When this occurs, there would likely only be a few plants affected, unless the container were enclosed (I recommend against those "mini-greenhouse" flats for that reason, they are fungus breeding grounds). But if you were to then start the next year with some containers already infected, it would be giving the pathogens a chance to develop & spread more quickly, and the losses would greater. I would add that the sterility of soil & container can be rendered moot, if the water used to dampen them - and the fingers & tools used during planting - are not also sterile. I use rubber gloves when planting, and RO filtered water or boiled rain water for seed starting. If I add an organic fertilizer to the water (which increases germination in old seed) I boil it before use. Once the plants are growing (and have their first true leaf) the sterility of water is probably less important. " I run a fan over my seedlings, and I spray with peroxide and water if I suspect any funny business, and I sprinkle with cinnamon, etc. and it seems to work. I grow very healthy seedlings that go on to be very healthy plants." I like the peroxide idea. It might be even more effective if it were used preventively (before symptoms occur) rather than correctively... it would be interesting to test that idea, and determine the dosage & periodicity that are most effective. It's worth mentioning, though, that peroxide also does not fit into a self-sustained philosophy. There might be other solutions (perhaps herbal teas) that would offer an alternative. For what its worth, I think Madhacktress & the original poster are on the right track philosophically... the vast majority of gardeners do not use sustainable methods for seed starting. If the economy were to go sour, there could be increased interest in this topic.
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Just about any media will do: slightly moist is important. If it's too wet, seeds go mouldy or drown and smother. If it's too dry, they wizen up and die of lack of water. Slightly moist will feel slightly cool in your open hand, but will not drip when squeezed hard. After that, any container will do, a small jar with a lid and about half full so there is air, a plastic baggie, again half full for air, a plastic tub with a lid...anything at all. Once every few weeks, check that it's still slightly damp and open the top for fresh air for a minute or two. I've used damp sand, damp peat moss, damp soil, damp compost and used tea bags. All are good, just be sure they are only slightly damp and check on the seeds from time to time. Assuming it is a species where the package of seed calls for stratification in cold conditions, then that is what they need. If you name the species I can look it up for you and post the recommendations for stratification. I have only grown the species around here myself, but would be happy to look up the requirements for something else for you. I have a copy of the seeds of woody plants manual.
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The past couple years, I've bought that Scott's Seed-starting mix, moistened it, placed in plastic drinking cups, sprinkled on seeds, sprinkled on a thin layer of dry mix, covered with saran wrap, and placed under my HD 500W worklights. This year I did this using some yogurt cups that had clear lids and started tomatoes and a tomatillo in that setup. I also started scarlet runner beans & hyacinth bean vine in re-used 6-packs covered with saran wrap, and cypress vine in one of those clear plastic salad bar containers. Nearly all of the varieties had sprouts within about 1.5 weeks (from seed that was new - 3 years old). Once the first sprouts were up, I took the cover or wrap off and bottom watered only. Once the veggies hit the 1st set of leaves, I transferred plants to 16 oz solo cups and pure moistened Promix, and eventually transplanted to 1 gallons a couple weeks before planting out. The others remained in their original starting containers and were planted out from that. The lights were on 16 hours/day and I have one of those small fans that I use to gently blow across the area. The downside to that particular seed starting mix is that it is heavy peat-based, but because I continually bottom watered, I tried to keep it generally damp on the way to dry (but never completely "wet"). One of my sisters gave me one of those clay basil balls and just before Memorial Day, I basically stuck that on top of a 8" pot of Promix, watered it, and put it outside. It sprouted once the temperatures shot up: I am going to be starting some more basil (Genovese and Purple) probably this upcoming week but will have the starting containers outside in the sun.
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zen_man
10 years ago
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.

ZM
ken_adrian Adrian MI cold Z5
10 years ago
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]

ken

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

ZM
floral_uk z.8/9 SW UK
10 years ago
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
tapla (mid-Michigan, USDA z5b-6a)
10 years ago
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?

Al

This post was edited by tapla on Mon, Feb 24, 14 at 10:03
grandmamaloy
10 years ago
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
tapla (mid-Michigan, USDA z5b-6a)
10 years ago
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.

Al
rhizo_1 (North AL) zone 7
10 years ago
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.
samhain10 - 5a
10 years ago
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.
tapla (mid-Michigan, USDA z5b-6a)
10 years ago
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.

Al
samhain10 - 5a
10 years ago
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.
runswithscissors
10 years ago
One thing I didn't see mentioned...is 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.

Best medium for starting seeds

Comments (14)

mandolls

tapla (mid-Michigan, USDA z5b-6a)

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