Sterile Soil

[matermaniac]

Hello all.

This is my first time growing heirloom tomatoes. I've been told that I should plant the seeds in sterile soil. But do I need to have sterile soil once the plant get's ready to go outside?

Also, what is the reason behind sowing the seeds in sterile soil? I've been searching for an answer for about 3 weeks now but can't seem to find anything.

MM

[Blueaussi]

A sterile seed starting medium, for certain values of sterile, won't have any stray seeds that will pop up and compete with your seedlings, and it won't have any plant pathogens like the fungus that causes damping off. These mixes are sometimes called "soiless" too, because they're mostly made of peat or other non-soil substrates like coir.

I really liked the Happy Frog potting soil that I used last year, and it was anything but sterile. It was jam packed with beneficial organisms and my seedlings thrived. Everybody has their own favorite, and some mix their own. My advice is to stay away from teh Miracle Grow type potting soils that have high nitrogen, time released chemical fertilizers in them, but there are those here who would argue that with me.

[PaulF]

I won't argue, but I have used the Miracle Grow types for several years without a problem. I just bought some non-fertilized starting medium to compare again. As always there really are not many absolute rights and wrongs, just different ways. I would suggest start conservatively the way most say is the preferred method, then go your own way.

[mtbigfish]

As Blue mentions soiless - what you use is a good seed starting mix - not soil
Dennis

[matermaniac]

So only the seeds need to be started in sterile soil. And it doesn't really matter that much when it goes to its final pot?

I started some saved seeds from last year in Jiffy seeds starter as well as some using garden dirt. I have Isis Candy, Black Cherry, Black Zebra, Orange Strawberry and Fargo in that and just about all have sprouted up and doing well under the lights so far. I planted these before being told about sterile soil.

Last night I started Mortgage Lifter, Purple Russian, White Habanero, Bolivian Rainbow Pepper and Cascabels all in seed starter and miracle gro. The mix was baked in the oven to 180F according to several procedures found online.

Today I plan to start Ivory Pear, Green Sausage, Cherokee Purple, more Tabasco Peppers and maybe a few more.

In the long run, I'd like to have about 5-10 plants for each variety. If I need to plant these things all in sterile soil, that's a lot of baking dirt.

Thanks for the help.

mm

[PaulF]

I don't understand "baking" the soil. A bag of soilless mix, Miracle Gro brand or Schultz or Jiffy or one of the other brands is pretty cheap and easy for potting up seedlings.

A starter mix has no slow release fertilizer and the Miracle Gro, etc. does. They are all considered sterile enough to use from seed to seedling to transplanting outside. I do not think anyone would recommend using regular soil from the garden, baked or not, for the indoor propagation process. Save time, effort and I think money by using bagged soilless mix inside and save the dirt for outside.

[Blueaussi]

If you're buying a commercial seed starting mix or a name brand potting soil like Miracle Grow, you don't need to bake the soil. They should be relatively clean, if not sterile, and not cause any disease problems.

You can bake soil from the garden to use as a seed starting substrate, that would get rid of any pathogenic organisms and most feral seeds. It would also kill any beneficials, too.

[matermaniac]

Thanks everyone for clearing this up for me. I hate going into some things completely blind. I'll keep the oven to roasting the maters instead of dirt.

BlueAssie, where are you located in SC?

mm

[Blueaussi]

Originally Posted by matermaniac

Thanks everyone for clearing this up for me. I hate going into some things completely blind. I'll keep the oven to roasting the maters instead of dirt.

BlueAssie, where are you located in SC?

mm

In the Midlands, near Columbia. There are quite a few South Carolinian members here. If you look down to the Regional Group Gatherings forum under SPLATT, you'll find information about the local gathering.

[brokenbar]

Originally Posted by matermaniac

Thanks everyone for clearing this up for me. I hate going into some things completely blind. I'll keep the oven to roasting the maters instead of dirt.

BlueAssie, where are you located in SC?

mm

Roasting dirt...Does it stink? When compost catches on fire, it stinks (and burning horse manure or cow manure REALLY stinks...)

[nctomatoman]

Big problem with using soil/dirt instead of soilless mix for seed starting as well as transplanting in my view is possible presence of plant pathogens, as has been noted in this thread - which can lead to damping off of young seedlings - but, especially, the density/heaviness of some soils, which can prevent adequate air to the roots....in heavy rain, you can get to drowning your plants once the soil compresses down, and in the event that the drainage holes don't work well.

So the baking thing is not a solution to this - there is no substitute to purchasing a good quality soilless mix. Otherwise, all of your efforts could quickly go to waste!

[matermaniac]

Update-
I moved the seedlings that I had in a mix of soil and miracle gro today into individual cells of jiffy starting mix in 6 packs. Hopefully, there won't be any issues. Roots were long for being only 3 weeks old and stalks were alot stockier now thanks to a better grow light.

Since getting the grow light the seedlings have gone from leggy and pale green/white to dark green, stocky and purple stems.

Now it's a waiting game for the rest of the seeds to sprout.