Seed starting mix

[Cranraspberry]

I know this has been discussed countless times before, but why not start a 2023 thread. What is everyone doing for seed starting this year?

I personally have not had great luck with peat-based mixes. Tried Jiffy last year, Espoma this year and even a nursery house blend potting mix that was quite fine. I’m sure it’s operator error, but I can’t seem to find a good balance of water with the peat - it’s either soggy and growing algae or so dry it’s forming a crust, even if I add more perlite. So I’m experimenting with adding pine fines and coir to the mix to see if I can get better drainage and more air to the roots that way. Not sure if the fines could negatively affect growth by tying up nitrogen? I guess we’ll see.

[JayneR13]

Indeed, once the peat is wet it stays that way and that causes its own problems. I've used Miracle Gro Seed Starting mix successfully for years. Last year I tried Espoma and had nothing but problems so this year it's back to the tried and true. I've had good luck with it. My 8 week seedlings have very well developed root systems and are of a good size for planting. Watering is a very delicate balance, no doubt about it! I check mine partly by heaviness of pot, and if the pot is light the plants get a good drink. A bit heavier means less water required. I check them once per day. I may not be perfect but this works for me!

[karstopography]

Baccto premium potting soil in the container cell with a thin layer on top of jiffy seed starting mix. The baccto is reed sedge peat, perlite, and sand and provides nourishment for the seedlings. Baccto potting soil maintains good moisture and won’t suddenly go dry like potting soils based on sphagnum peat.

I haven’t lost a tomato or pepper seedling yet or had any sign of disease.

[Cranraspberry]

@JayneR13 thank you! I’ve actually read lots of good about the MG mix, but isn’t it also a peat and perlite combo like Espoma? Jiffy had vermiculite and peat, which caused even more issues. I also tried a “fancy” Organic Mechanics peat-free mix last year and it was the worst of the bunch - pine fines, rice hulls and coco coir were the base.

@karstopography that Baccto sounds awesome, I believe I’ve seen some youtubers recommend it as well. Our local nursery carries their The Cow manure product, but unfortunately not the regular soil.

[brownrexx]

I use commercial potting mix, Espoma, I think and I have never had problems. I think that the temperature of the room makes a big difference. I start my seeds in my sunroom which is about 74° and I never have mold or damping off. I also do not subscribe to the idea of bottom watering and sometimes have the pots sitting in water. I water from the top daily and as I said, I never have problems.

Many people start their plants under lights in basements and that air is much cooler and damper many times.

[Cranraspberry]

I read over on houzz that someone was doing a 1:1 mix of MG fine orchid mix (I don’t think they make it anymore, but I believe it was small bark fines) and potting mix and that the additional loft/drainage really did the trick for them. That got me thinking about the pine fines. Our nursery carries Norfleet’s Special Blend which is really tiny, but hopefully they will do more than perlite alone.

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[Kingbird]

Coast of Maine seed starting mix is the best I have found to date.

[Cranraspberry]

@brownrexx do you use the basic Espoma Organic potting mix in the green bag? I bought a large bag of that for potting up. Got greedy and bought a giant 2 cu ft bag which is probably more than I’ll need for a few seasons. Glad to hear you’re having good results with it.

[Cranraspberry]

@Kingbird we get a lot of Coast of Maine products at our local nursery and Ace Hardware, but unfortunately they don’t stock the seed starting mix.

[Toomanymatoes]

SunGro Sunshine Mix#4. Not a seed starting mix, but it works just fine for me. I switched because it is much cheaper. I used to use Jiffy Seed Starting Mix, which I thought was the best out of the several I tried (best because it had WAY fewer large pieces compared to all the others I tried, they did not seem any different than regular potting mix).

I like the Sunshine Mix because it has a lot of perlite in it. I think ProMix HP is similar.

[Seven Bends]

I read over on houzz that someone was doing a 1:1 mix of MG fine orchid mix (I don’t think they make it anymore, but I believe it was small bark fines) and potting mix and that the additional loft/drainage really did the trick for them. That got me thinking about the pine fines. Our nursery carries Norfleet’s Special Blend which is really tiny, but hopefully they will do more than perlite alone.

I think this approach could cause more problems than it will solve. I think you'll have better success by using a standard seed starting mix and just being careful about the watering. Don't overwater. I agree with @brownrexx that bottom watering can cause problems if you let your pots/packs sit in the water too long and get the mix too saturated. Let the mix dry out a little between waterings -- not DRY, just light.

I've used Jiffy seed starting mix for my starts so far this year (because it was really cheap at Walmart) and it does have a tendency to hold water for a long time, so I'm only watering about once a week. My onion seedlings are doing fine.

The only seed starting mix I remember having truly bad results with was a Fox Farms product -- I had to repot everything because the seedlings were stunted and just not growing at all. Black Gold, Espoma, Miracle Gro, and ProMix seed starting mixes have all worked fine. So have all of those brands of potting mix, with the large chunks picked out.

I plan to use Miracle Gro yellow bag potting mix (chunks picked out) for my tomato & pepper starts. That's what has worked best for me in the past.

[bower]

Last year I used about 1/4 promix to 3/4 compost iirc. Peaty mixes don't work well for me because of the cold seed starting environment - they are either too wet or too dry very difficult to keep conditions optimal. The promix is certainly peat, I haven't got any this year and am using just compost and perlite for the non-tomato winter grow. And a handful of sand in the mix I made for peppers. Getting some mossy green growth in a few places, mainly on cellpacks that were overwatered. So I may go ahead with this for the tomatoes too.

[brownrexx]

Oooops @Cranraspberry it looks like I mispoke about my brand of potting mix. I have used Espoma in the past and it worked fine but this past year I bought Coast of Maine OMRI Organic potting mix and that is what I have left over to use again this season.

Honestly I have never paid any attention to the peat content or anything else. I do however swear by buying it at my seed store where I know that it is fresh and stored properly. I have seen bags of potting mix in the big box stores with clouds of fungus gnats flying around the bags and I do not want to bring them home.

[zeuspaul]

I use Mosser Lee No Damp Off seed starter. It is long-fibered sphagnum moss which is supposed to help prevent damp off. I use just a tiny amount. I form a small well in the potting mix and place the No Damp off in the well and then place a pre germinated seed in the long-fibered sphagnum moss. The mix is anything I have around with chunks sifted out. Mostly recycled mixes. I pre germinate seeds by first soaking in water for about 8 hrs. Then I place the seed on top of a clay brick in a pool of water that is kept warm and covered on a hot plate. I place a thermometer in the water to monitor the temperature.

Most of my damping off problems disappeared when I avoided placing the seedlings in a cold wet environment. I use to place the seedlings outdoors in sometimes misty cold morning temps.

Mosser Lee No Damp Off seems to be *out of stock* everywhere. I still have a couple of bags so I am good to go. When I have to replace it I will likely opt for Mosser Lee SucSeed and still use the well method.

SucSeed™ Seed Starter: The Ultimate in Seed Starting™ is an exceptional organic seed starting medium. Milled long fibered sphagnum moss has been recommended by professionals as the only renewable seed starter. Made from Wisconsin-grown long fibered sphagnum moss plant, SucSeed™ is free of peat, which can contain harmful damping-off bacteria that could kill your seedlings. SucSeed™ Seed Starter gives your seeds the best chance of achieving the highest seed germination rate available. 244 cubic inch (4L) package.
https://www.mosserlee.com/product/sucse ... ng-medium/

[Greatgardens]

I'm really interested in this topic, since I am a chronic over-waterer of my seedlings. I'm going to start a few plants this season using cactus mix, which as you would expect is very sandy. I will modify it slightly with some regular potting mix and dry fert. I'd like to try Pro-Mix HP, but I don't need a big bale. I haven't found anything smaller.

[Cranraspberry]

@Seven Bends I just started some lettuce and brassica seeds in two starting mixes - some in the Espoma mix, and some with Espoma plus coir and fines. That should help determine which way to go with peppers that are due to start in a couple of weeks!

Watering properly SHOULD be the answer, but for some reason I just can’t get it right. Especially with the smaller 1” cells I end up with situations when some of the seedlings are sitting in mix that has mold and algae while others are crusty and the peat is separating from the sides. All this with bottom watering.

[zeuspaul]

@Cranraspberry I have no idea where you are located. I don't know what DMV stands for other than Department of Motor Vehicles. Google is no help and agrees with me.

[Cranraspberry]

@zeuspaul it’s the National Capital region - DC/MD/VA aka DMV.

[Cole_Robbie]

Covering the seeds with vermiculite is essential for me, and seems to make any mix work fine.

[GoDawgs]

I've used a variety of mixes over the years, usually changing only if the mix recipe has changed, like gotten too rough. Currently I'm using Happy Frog. My seedlings seem to do well in any of them.

Rather than soil mix, the keys for me are covering newly seeded containers with plastic wrap (removed immediately when the first seeds pop up) checking moisture levels every day and watering only when necessary (when the packs/pots start to feel a bit light), making sure there's no standing water in the trays, always keeping the lights about 2" above the plants(lights are on chains) and giving them a small shot of Miracle Grow now and then beginning when the true leaves show up.