What is a good seed starting soil mixture or premixed. I have had bad luck with commercial soil. Give me ideas for something simple and inexpensive
Premier Pro-Mix BX is a general purpose sphagnum moss growing media. I have had good luck with it. Buy it in the large bail and it will be cheaper than buying smaller bags.
I have been reading this book Square Foot Gardening and the author speaks aggressively about starting seeds in vermiculite. He mentions it so many times I have just got to try it next year.
I've done my share of seed starting. I've paid for peat, perlite, vermiculite, etc. I've also started seeds in paper towels in a plastic bag or on moist cotton balls in egg cartons. But now days most of my seeds are getting started in whatever dirt/compost mix I have on hand. I've actually had good luck lately mixing compost with sawdust to start seeds.
I know people say you need steril seed starting mix and some people say to wash trays and pots with bleach but I haven't done any of that for about 10 months now. I haven't been having any trouble with damping off since I quit buying "special dirt". Biggest trouble with the sandy compost for seedlings is the tendency for it to be chunky so filling seed pots can be tedious sifting through things. I guess that was one reason I mixed in some sawdust to make it a bit finer.
Of course your mileage may vary.
In reality a Good Seed Starting Soil will not be a soil at all but will be a mixture of a material that will hold moisture fairly well but will also drain quite well, a soilless mix of some kind. Many people mix compost with either vermiculite or perlite (both of those help with drainage) and many others mix either peat moss or coir or finely shredded bark in the same way. Most all mixes available at the stores are one of these products.
Seeds need an evenly moist medium to germinate and grow in. Some seeds need a medium with a temperature around 70 degrees to germinate while many others will not germinate at temperatures that high. Too much moisture is anathema to seedlings because in addition to moisture their tiny rootlets need air to grow.
Jiffy mix, Pro-Mix, Metro mix 360, 1/2 & 1/2 compost and peat, 1/3 each of peat, compost, and vermiculite have all worked well for me. Just make sure it is nothing with dirt (soil) in it for best results.
I typically mix peat and perlite, germination rate is usually close to 100% if I wait long enough for the 'slow' seeds. I moisten the mix, fill seed starting trays, just press the seed onto the top of the mix, cover with about 1/4 inch of vermiculite.
I am sure that there are many acceptable mixes for starting seeds, this is just the mix/method that I have been using. Works well.
The only 'soil' that I have ever had problems with has been Miracle Grow, Moisture Control. Apparently 'moisture control' is another phrase for 'doesn't drain, stays soggy'. At least that was my experience.
My experience has been that getting a seed to germinate is fairly easy; growing them to transplant size is the tricky part. I have always had trouble with seedlings developing deficiencies in soil-less media.
I should state that I start them early in a cool greenhouse and that they are in the tray for a while.
Unless they are getting fertilized with something like miracle grow in the irrigation water with every watering they will turn yellow or white and might or might not pull out of it when transplanted (if they live that long).
I tried all sorts of combinations of materials and found that having soil in the mix helped with the deficiencies. I now use a mix of screened sterilized soil, sand, and organic fertilizer with micros. I would like to add some peat to help keep the mix from seeping out of the drain holes in the trays, but I have a lot of trouble with fungus gnats and they are only a problem if peat is used.
I also put together an automatic misting system which makes life a lot easier and vastly improved the germination and quality of my seedlings.
fertilizersalesman, how do you sterilize the soil? The few times I've tried using soil, I've had problems with damping off.
Personally, I have great success with a 50/50 mix of sterilized builders sand and screened peat moss, I sterilize the sand with a 10% bleach solution and rinse twice, then let it dry thoroughly. I then store the sand in sealed zipper bags for use when I need it. Screening of peat moss and sterilizing sand is done during times when I can't get into the garden and these are stored for later use when I need them. I place the sand in muslin bags during the sterilizing process to to make it easier to handle after it is wet. I germinate on a heat bed set at 65 to 70 degrees F and find that the sand holds the heat well so the temperature doesn't fluctuate so much and cover (but not seal) the germinating flats so it will hold in some moisture but still breath. Once the seeds start to germinate I use a water-soluble fertilizer at one quarter strength with every watering and uncover the flats. Adequate light is normally more of an issue along with adquate air flow. These are remedied with suplemental grow lights and a small oscilating fan set far enough away to create a breeze accros the plants to help make the seedlings stronger. In more than 40 years of gardening, I have never had really good success using unsterilzed compost or garden soil and sterilizing these in the house I would never recommend unless you have a dead sense of smell.
Here is a link that might be useful: jerrysplants.com
The greenhouse that I start my plants in steam sterilizes their soil and I just steal some.
I have had really good success starting some kinds of seeds right in the free compost we get from the county. I've had 90-100% germination with sorghum, amaranth, tomato, squash, zucchini, pumpkin, cucumber, several different herbs, and okra. Lower rates for corn, onion, and carrot seeds though that is probably not because of the compost. I have not had much trouble with damping off. Granted, I am growing outdoors and not inside. There seems to be more trouble with damping off of my lettuce when I'm trying to grow it indoors. I haven't really had much luck with lettuce outdoors, it has been too hot since I moved here.
I have concidered making a solar oven for sterilizing planting media.
Screened home-made compost works pretty well for me, except for the damping off problem. If the seedlings aren't affected by damping off, then they do very well and seem to appreciate the nutrients of the compost.
Hillbilly - just to make sure I understand your process... you fill muslin bags with sand, then dip the bags in a 10% bleach solution? How long do they stay in there? Then you dip them in water baths to rinse? I might try it this year. I've got a pile of leftover mason's sand out back. Anybody happen to know what the difference is between builder's sand and mason's sand? Also, I'm wondering if you've ever tried play sand, which can usually be purchased pre-sterilized. I'm guessing that the grain size of play sand is too coarse?
Wow thanks everyone for the responses! I've written all these recipes down for me to try out on all the new seeds I'll be getting. It's interesting how many different varieties of mixtures their can be to grow seeds in. Keep the recipes coming!