We tested popular seed starting soils: you'll be surprised to learn which one did best! 

This information is so valuable! Have agreed to move away from peat. Gardeners like you make gardening easier for us beginning seed starting guys!!

I can attest to your coco loco, green sand and coco fiber recipe! It is seriously the bomb! I have tried a lot of recipes over the last few years and this one is THE BEST!! Thanks for sharing!! And yes, I started with the pods too and am still finding them completely intact years later in my garden!!

Thank you for breaking things down and doing a very good comparison of these different soils!

Great video. Looking forward to seeing how well they all do in 4 weeks. Thank you for all of the valuable information.

Love the comparison because it confirmed why some of my starts have been lousy. Looking forward to using your recipe for 2024! :)

I love the idea of testing what works!! We're going to do the same thing, but with different types of water: river water, Berkey filtered rainwater, unfiltered rainwater, bottled water, and tap water. My husband is going to wire grounding rods so we can put them in with some of the plants and see if that makes any difference in germination and growth.

I've had very good results with Jiffy seed starting mix from Home Depot. I just pour boiling water over it to make sure it's not infected with fungus gnats. It works fantastic!

Thank you for doing this comparison. Good point about the container used vs. soil block. I have used Blackgold and didn’t like the muddy silly sand consistency when wet and didn’t seem to drain like I would prefer and poor plant health. I tried coir last year and it molded and holds a lot of water and if I used it again I know it needs a lot more perlite. I do have a soil blocker I haven’t used yet and I’m intrigued with wool and greensand along with coco loco potting soil as I’ve never used any of them before. I do believe the container makes a huge difference. My dilemma: This year I am using Promix potting soil inside and a peat/vermiculite/worm castings for winter sow jugs. The jugs I don’t know yet and think I should have added a bit of lime, but the Promix is having a bit of a mold/mildew issue. Furthermore, and I’ve never-ever had this problem before, are Aphids on herbs and artichokes inside! I’m using premixed Neem oil and it seems to help. I use a fan and the cell packs are drying unevenly so I water the dry ones sparingly. It’s been a battle up to this point, but I’m not losing my onion starts again. Surprising the aphids are on lemon basil, marjoram and cumin, but not on rosemary, thyme and oregano. They are all close together so at least I know what aphids don’t like. They say over water is what causes mold and aphids and gnats, but I’m not heavy on the water it’s just inconsistent drying. I read an interesting article about peat on Growertalks.com on ‘Is Peat Sustainable’. They interviewed a long time employee of Premier Peat along with other scientists. It thoroughly explains its sustainability and how they reclaim the peat bogs and really how few acres are used. It also explains Europes dislike of its use and that’s more to do with small area they harvest. However the biggest threat to peat bogs is in coastal areas where the oceans have risen due to glacial melting and bogs can’t grow in salt water-so global warming appeared to be the main threat. Coco coir others say use a lot of resources by shipping and the need to rinse the salts out of it before use. Thank you again and I don’t know where to find the potting soil, greensand or wool, but I will google or check if you listed. There has to be a better way that doesn’t mold and I’m using air layering cell packs. Maybe if packs were on a tray and not 1020 tray. Of course cost is important also and I’ve seen expensive potting soils. I wonder if I used your soil block recipe and blocker if it would mold inside-it could be because it’s warmer in the house. Sigh, I so need to rework my lean to greenhouse so I can heat it more efficiently and keep all this mess outside. I’m hoping to find answers and today I used a light mix of fish fertilizer as I’m growing lettuce successfully and I’m glad I used it lightly as the odor is not pleasant. May have to heat that greenhouse sooner.

Thank you for taking the time to make these videos- so helpful!

Love the science and test runs. I start a lot of seed trays but also do some direct sowing just to see how the garden bed soil is doing... and what bugs are waiting for a plant buffet.

Very good info. I’ve never heard of the cotton pellets. Can’t wait to see what they look like in 4 weeks

Nice video! I use Pro-Mix all purpose mix. Once my starts grow their first set of true leaves I start feeding them fertilizer. Usually Alaska fish fert but sometimes I use Jobes or espoma organic in my Pro mix from the beginning. I really haven't noticed a difference either way. Nice strong starts every year. As far as peat moss goes, I don't see anything wrong with using peat based products but that's just my opinion.

I think the main take away is give your plants' options of nutrients, deliveries and water retention to an extent.

i started using the Burpee Organic seed starting mix with coco coir this year and it seems to be doing all right. They also have pre fluffed coir in a bag I can mix with my own potting mix. I used the jiffy last year and I am trying to do a comparison this year but so far they seem about the same. I also wish the sheep wool and green sand was more available. Thank you for the video!

Okay I came back to comment after using this recipe, holy cow it's the best results I've had since attempting soil block this past spring! Thank you!

Thanks for this important and informative video on seed starting ! You are right, a good seed starting mix makes all the difference in starting seeds and keeping them healthy . This is one of the best seed starting videos that I have seen. Good job !

Thank you for doing this- I learn so much from your videos! Also, thanks for the info re peat. I didn’t even think of the carbon release issue. I won’t use it again!

Interesting comparison. I have used black gold brand and had great results but I also start fertilizing with fish emulsion and bottom watering method after germination.

Great comparison! I’ve seen a lot of gardening content and tests but haven’t seen a seed starting media test like this. This is clearly an important item to consider. Really solid content Briana, thank you.

Great explanation! Thank you!

Love this. I am planning to do something similar here to find the soil blocking recipe I like best. You encouraged me to try the wool pellets so I'm anxious to see how it does. Thanks for sharing.

Girrrrl I’m so glad your channel found its way to me! I’m OBSESSED WITH DIRT NOW! Lol

Really interesting, thank you.

Another EXCELLENT video! I love this channel. I've learned SO MUCH in the short time that I've followed you. As an aspiring flower farmer I feel like I'm going to be able to bypass many, many mistakes after binge watching all the videos. My question today- do you ever put mycorrhiza in your seed starting blocks or trays? Another recipe, the first I ever came across, used a small amount in the soil blocks. It's in an additive that they sell that is essentially green sand and mycorrhiza. Any thoughts on this? THANK YOU for continuing these amazing tutorials. I really look forward to seeing the notification that you've posted again....brightens my day ! !

Great stuff! Thank you.

I used the Burpee Organic that's made from coconut coir and it's worked really well!

New to seed starting and your video was really helpful. Thanks for doing the work for us! Purchased starting mix with 88-98% sphagnum peat, perlite, poultry liter and yucca OMRI listed so will use this but now I have several other choices. Love your channel 🌿

Because our well water is very hard, I have been collecting rain water for my young plants and they are much happier with that. Once planted outside in the garden, the plants are fine with the well water, because rain helps to dilute some of the minerals. I like to start zinnias in containers outside before planting them in the garden, but I just use garden soil for them. They grow just fine. Potting soil definitely varies a lot.

My second time watching this very informative video! I've now bought wool pellets and am getting myself a swiftblocker for Christmas! :-)

thank you so much for all your information. I now have my greenhouse but I will need to run electricity to it this year as I do want to start seedlings.

Loving this video 👍 the way it is laid out to test these seed starting mixes with a scientific mindset, appreciate how much thought you’ve put into it! I used miracle gro last year, and am using Jiffy. So this comes very handy as I do wonder if there is any difference between these 2 brands

I really appreciate the SHOW and TELL application rather than just the TELL. Thanks for putting that out. At the same time I conducted a mini trial on my seedlings using a seed starting mix (Huffman? - I had it on hand) and plain Canadian Sphagnum Peat Moss. Using the Epic Gardening Cells (LOVE LOVE LOVE) I noticed that the seed starting mix did not up take water as quickly as the cells with the peat moss. Quite unofficial compared to yours but I was using what I had on hand. My question is what is it that you do not like about peat moss? Unsustainability or just not good for plants? or both?

Thanks! Great info!

Love these tests! I don’t think I have coco loco available to me, so I’m using coco coir with compost. I used to use jiffy as well, in Minnesota it can be unpredictable with planting out and it was difficult to keep them in jiffy sometimes due to weather delay so I’m happy to see these helpful tests with a bit more nutrition. 👍🏼

Great video, very informative.

This was a cool experiment! I was really surprise with your recipe with wool pellets when not in soil block! Glad to have watched this bec I got the supplies for your recipe except was gonna use it with trays. Can’t wait for the updates

Thanks for this! I've been looking for an alternative to SunGro's Propagation Mix (#5) because it contains peat moss. One thing I was taught by the founder of San Diego Seed Company was to use sterile seed-starting mix to avoid damping off and other pathogens I guess? Then we add diluted fish emulsion once germination has occurred and the first true leaves appear so everyone has enough nitrogen. I'm also excited to watch your nettle fertilizer video. We have SO much stinging nettle here right now (cool season in San Diego/Zone 10a), and I'd love to put it to use! Thanks again for your videos!

I use potting mix as opposed to seed starting mix to start seeds. It sounds counterintuitive, but I have found that the potting soils/mixes feed the seedlings and I don’t need to bother fertilizing. BUT seeing your results from your recipes definitely makes me want to try them myself!!! Happy growing. 💚🌱

Loved the video! I use a mix that my local garden center makes with great success, though it does contain peat moss. Next year, as I already am stocked up for this year, I will try your coco core formula and work towards reducing my peat moss use.

I've not had great luck on Jiffy by itself and adding liquid fertilizer after they get growning some, so I've started mixing it in with some of the potting soil. But I might be willing to consider the miracle grown mix as an all on one, to save some more while we are still building beds an other structures in the garden. Then I can work towards something like your recipe (not sure if I can get Coco Loco locally) when have more money to spend on it.

You Rock!!🤩🤩 Thank You So Much!! Wool pellets are on the way to me within 5 minutes of watching this!! 🐑

This is an awesome test. The results is the proof in the pudding you did an exelant presentation on point and precise thumbs 👆 thank you I'm gonna check out your other videos

Great video!

Thanks for sharing this

Well done

There I an article in the April 2024 issue of Greenhouse Management with updated information about the horticulture use of peat which also has comparisons of the environmental impact of using peat vs coconut coir. Very enlightening.

Small Block 3 Quarts Peat 1 ½ Quarts Compost ½ Cup Green Sand ½ Cup Rock Phosphate 2 Inch Block Parts Measure Additive 2 Bucket 10 qt Peat Moss 2 Cup Azomite Mix 2 Bucket 10 qt Perolite or Course Sand 1 Bucket 10 qt Peat Moss 1 Cup Azomite 1 Cup Green Sand 1 Cup Rock Phosphate 1 Cup Blood Meal 1 Bucket 10 qt Peat Moss Mix 2 Bucket 10 qt Compost Mix

I found the information very useful.

This was Awesome! Could you possibly do a Soil block v cell trays v winstrip video?

I’ll be trying Espoma seedling mix this year.

Seeds sprouted easy in fine jiffy mix at top. Also.be careful of any mix with perlite vermiculite be careful you dont want to breathe in any soil mix mask ventilation or if lot of pots fill outside. Moisten mix too can help

Grateful for your comparison, it explains a lot of what happened to me last year..thinking I was doing the right thing, I did make that mix of perlite, vermiculite and coco coir…and it bombed. So ok, but I also thought that a seed starting mix did not need nutrients…my other favourite mix is the pro-mix which has micorrhizae, limestone, perlite, coir, peat moss, and has organic fertilizer ( surprised! Didn’t know). My challenge is to keep the seedlings alive after potting them up, i think the same is true with potting soil, not all made the same. I am in canada, and the movement for peat free can not prevalent here but I did buy coir blocks but haven’t found a recipe that work, so haven’t used them…where can I get green sand…Gaia brand I saw but pricey. Thanks again for your video!

I've been extremely happy with the Espoma which includes mycorrhizae inoculate. Seeds don't need fertilizer until they are ready to pot up anyway so it's usually not necessary to include some, but I still like to mix them into my starter mix anyway because the mix goes with the plants when they get potted up

I wish someone would do this with Australian products! I've been mixing half-half of worm castings and a fine "seed raising mix." The seedlings just don't grow much, so I'm planting out teeny weeny stubs with 2 true leaves. They grow so much better in soil.

Love your videos, so helpful. Do you have any suggestions on how to control fungus gnats?

Thanks for this! We really like Fox Farm brand :)

Very interesting - my science brain loves a good gardening experiment. My experiment for this year is 8 (!) varieties of winter squash. I'm a bit surprised at the results re: the Black Gold, which is what I have sitting downstairs.I've always jazzed it up a bit, so I'll go 'round to the garden center to see what they have in stock by way of coco loco and greensand to add to the current supply. I did order some coco coir this evening, and have raw wool skirtings downstairs. Next year I'll definitely lean into the coco loco/coir/greensand recipe, with some wool tossed in. Thanks so much for an informative video.

Very interesting! I have a pretty different style of seed starting focusing on peppers and tomatoes -- I start with Jiffy in small sixers just to get germination, then plant out to 2.5", 3.3", and 5" pots as they grow (4 weeks is about when I'm starting to move from 2.5" to 3.3" pots). I assume the seed starting mix will be kept warm and wet and fairly sterile for a limited time, (e.g. 2 weeks). Then I add soil with good balanced nutrition after that, but without a humidity dome or heat mat. I plant the seeds differently too so as to avoid "helmet head". This could call for several additional growing tests (which I also do often, as well as keeping detailed notes) but my impression is that my method probably requires more labor early on, and is oriented more towards plants with less easy germination. One more thought -- do any of these starting soils have advantages when you are continually trying to avoid fungus gnats taking over?

I have added smaller amounts of blood meal and bonemeal to regular seed starter soil with very good results and now I will add greensand..thanks

Greensand seems to be a winning ingredient in most testing I've watched, Fertilizing is also a must, hence mg...

Why the thumbs down on peat? Most of the negativity about peat was spread by the coco coir investors. Peat is a regenerative resource that is massive. Peat bogs go as far as the eye can see and yes it releases carbon but coir has to be shipped much further distances often across oceans releasing far more carbon into the atmosphere and is often processed with extremely powerful grinders that run on huge amounts of fossil fuels. I've used every starter and potting mix and found Back Gold to be the best. You just should add some KNF nutrients for explosive growth. By water volume per gallon 1 to 500 (8 MLs) fermented plant juice 1 to 1000 (4 MLs) fermented fish amino acid ,vinegar extracted calcium and phosphorus and some humic acid. The results are amazing..

Have had really good success starting my seeds directly in Happy Frog potting soil, skipping the seed starting mix entirely. It does have extra amendments to help the seeds grow after germination and is Omni approved.

I have been doing research on a few recipes for soil bocks and I am curious if the peat moss/vermiculite perlite also flopped like the sheep pellet one due to retaining too much moisture? I cannot find cocoloco local to me and also before I had found your videos so I had picked up materials to do peat/vermiculite/perlite and half the peat for coconut coir and maybe try to add some things for some nutrients like some worm castings or mycorrhizal fungi or something. First time seedling grower and initially thought my biggest trouble would be picking seeds, then setting up my schedule of when everything needs to be done by….then how to set up my growing area.. and every step along the way has been another rabbit hole. Haha I just wanted to say thank you for a) taking the time to do these experiments and b) sharing the results for all of us learning from home. It is much appreciated and you did inspire me to start off by getting a soil blocker rather than oodles of trays, so your work is paying off!

This is a difficult task... It seems to me that we need to use the capabilities of a biochemical laboratory) Great video!

So, do seedlings need to be fertilized? If so, how often? Organic fertilizer to use? I started my seeds in coconut coir this year...

I was curious on the green sand as it's not a material I am super familiar with. In your opinion, what makes it a good option for your mix? From what little research I've done, it seems to be nonrenewable and I can't find sourcing in/near the US so I assume it's imported. Another thought - it's harvested from the ocean I presume, what sort of ecosystem disruption happens with that harvest? I was really impressed with how well your mix worked. Thanks for sharing your results!

Do you have a link for the green sand? I want to try your soil block recipe but dont want to buy the wrong thing. Thanks for the awesome content!

I tried the wool pellets but not sure how you can distribute it better. Pellets are hard to break up when dry & once soaked it kinda clumps & I have to tear the clumps apart as I come to them when mixing the recipe. I thought about putting the dry pellets in a blender/processor maybe to chop the pellets up before soaking? Kinda time consuming! Also the wool pellets are not cheap! I am trying it though just to see difference but haven't started seed yet. Thanks for all the info & trials you share. Will stay tuned...

Coco coir killed my tomatoes Seedlings! 200 small market gardner Water temp is also important. Store bought jiffy has worked well . Using 6 parts vermiculite, 1 part perlite, 1part worm casting, and finally 1 part 10:25 blood meal.

Use a surfactant when wetting peat and it is easy to hydrate.

Great video and not a worm in sight 😉

Hi Briana, thank you for this testing. I just came across this video in the nick of time. Can you tell ,e where you get your greensand and do they sell in smaller portions (2lb-3lb)? I see it on amazon but I would rather purchase local. I am in TX. Have not found it though. Thanks much appreciated. Also, Love Love Love your cut garden video. I am in the process of setting up a cut garden and your guide plan was genius!

Great video!! I'd love to do this. Question.... We build out a van and put 100% wool as the insulation. I have a ton of this left and not sure what to do with it. Do you think this would be a good substitute? It like a batting form though (not pellets). Thanks for sharing your wisdom!!!

What a worthwhile and telling experiment! Thank you for this important work. Your test results prove without a doubt the importance of the right mix for effective seed starting and plant growth. Please keep this going! This is potentially the most helpful and important and desperately needed problem solving information ever provided on seed starting. Indeed the secret is in the soil. You convinced me -and it’s really no surprise -many of my failures are due to using poor or the wrong soil. So I’m hoping your testing will provide the optimum mix that will wIll change me into a successful seed starter! Finally I have to say I’m amazed at you! Successful at growing the most beautiful and healthy plants already yet you are still improving and innovating for perfection. I’m following you all the way!

Great info! So for the wool mix with the soil blocks, did you do that a ratio of 4:1 or 8:1? I just got my soil blocker the other day and I’m getting ready to mix up a batch this weekend!

i would love to come see everything in your green house

I spin wool, could I use a little pinch of it in place of a wool "pellet"? Newbie at gardening. Thank you. Loving your videos. New subscriber 😊

Surprising to see Black Gold not perform very well. It's my favorite seed starting mix. It usually just needs a bit of fertilizer/food of some kind added to it, and the plants usually thrive. Plus there's usually never any random large chunks of organic material! Easier to fit into smaller containers for seed starting.

4:33 darn! I just bought some to uppot and when transplanting id try to compost it! Next year, depending on my success, i guess I won’t!!

Thank you for explaining the peat issue

Hello! Do you mind providing a link to where you purchased your bamboo stick from?

What can you mix with worm castings and grren sand to make soil blocks?

Interesting test. But I dont use seed starting mix. I use a good quality potting mix. This year it was promix because I got it at $9 a 2cu ft block. Its peat based, but I dont have a problem with peat since its Canadian and I am in the US. Coir may sound environmentally friendly until you take into account how its made and how far its shipped. Since I mainly do container gardening the plants will eventually be in my potting mix, and they start well in potting mix.

What is the soil recipe for the wool pellets? Also any tips on what type of fertilizers you recommend?

I found "Coast of Maine sprout island organic seed starter" excellent soil, much better than what they sell at the box stores.

For many years I use 1 part miracle seed starter 1 part coacoa core 1 part vermiculite 1 part pearlite. The coacoa core block is wet with warm water. All peat gets wet with mixing Seeds do not need fertilizer for first week or more. I use neptunes fish after true leaf and they grow great.

May I know what wood pellet I should use for the receipt?

Black gold was a huge fail for me last year. 3 entire flats of snapdragons germinated, but wouldn't grow! All my others using jiffy were great! I ended up plucking the seedlings and transplanting them with Jiffy and they did recover, but never had the normally strong stems. A soil fail at this stage is devastating, especially since I spend a fortune with Johnny's and usually can't just reorder most seeds that late in the game. I'm too afraid to try anything else now. I feel like it's not worth it! That miracle grow surprised the heck out of me too!!!

I am neR denver as well. Can you say where you buy the wool pellets, coco loco and coco coir???

Can you make soil blocks with coco loco and worm castings alone?

I like that you're smart 🤓

Thanks for doing this :) ! I hadn't remembered that about the carbon issue with peat, only the bit about it's sustainability issue. On that, some newer info calling that into question has arisen. I'm NOT supporting the willy-nilly use of it if and when we don't even "need" to at all, or for places far from a source, btw, either tho. Back to the carbon - grasslands are a great carbon sink too though, and every time soil is tilled at all, carbon is released. Idk about amounts in various types of soil and if that can even be reliably accurate as I'm guessing OG matter content, moisture levels etc. all may play a part in any plot of land on a given occasion. Anyway, I'm not saying just because we should all be doing and supporting minimum, light &/or no-till ( OG) systems and increasing land grazed and changing all grazing to Savory's trouble-shooting, reliable way of implementing and managing rotational grazing. Thus creating top soil, dense & diverse stands of grasses etc., cleaning and holding water, sequestering carbon etc. ( watch Alan Savory's presentations. If you watch stuff from naysayers, at least also watch the rebuttal vlog by Sheldon Frith, thoroughly - but pleasantly & simply- addressing a main one). All that still doesn't prove carbon from our soils is causing the issues they say it is or will.... and a LOT of real, experienced, accredited scientists differ from the mainstream on that and other related topics, but aren't given much of a hearing, and in other ways truly have been worse than ignored. So, my point is that there may be a whole lot more to this story, so I hope everyone takes everything with a grain of salt, does more, prayerful research and hears from other "sides" and just does their best to be good stewards, and to keep local, all-natural etc., as best they can ! Not saying we don't make mistakes or need to learn from them !

Anyone know the updated version to this 4 weeks later?I tried to find it and I couldn't. Thank you!

you only need vermiculite for seeds then transfer, seeds have their own growing medium within the seed and vermiculite holds water

Cqn i know which light you're using? I tried to grow rqdish inside twice and it just doesn't work for me. Thank you

I’ve only ever had success starting with hydrated coco pucks. I’ve tried starting in Ferry Morse, Jiffy and MiracleGro and they’ve all had issues with damping off or yellowing. If I put the hydrated pucks in larger 3”-5” pots with seedling mix after they germinate they do gangbusters, though, so it may just be a process thing for me?

how do you reuse your seed starting mix? the one you use to make soil blocks with the coco loco and stuff? that coco loco is pretty dang expensive so im wondering if you reuse it?

Well done. Maybe for your own sake, maybe using miracle grow as a soil block would be the most economical mix. The block allows lots of oxygen to get to the roots - the Japanese are using mesh baskets for bonsai propagation. Thanks

I agree with what you were saying about the miracle Gro mix for a vegetable garden wanting to be organic. But what are your opinions if you’re just using it for annual flower seeds like foxglove and viola’s?

Where do you source the green sand? I have been looking for it locally and have not found it. If you know a source please share. Thanks!