Boiling water to sterilize soil?

Since seed-starting time is upon us (at least for some of us!), I thought I'd share this tip I read recently.

Fill your cell packs (already sterilized and dried and ready to go, right?) with soil-less mix. Tamp down lightly and drizzle ~1 cup of boiling water over the top of a flat (72/48 cells, depending on size) - before you sow the seed.

The heat will dissipate almost immediately, so you don't have to wait to sow your seeds. According to the article, this sterilizes the surface of the soil, and reduces the risk of mold growing on the soil's surface.

I see another possible benefit - it should help the mix (mostly peat in most cases) absorb additional water better (peat takes FOREVER to absorb cold water.)

The article didn't go into detail beyond that, but I usually pour about 2-3 cups of warm water in the bottom of the flat (assuming it isn't one of those with drainage holes!) and let the cells become saturated, usually as I sprinkle my seed on top.

Now, granted, soil-less mix IS sterile already, but I thought this was an interesting idea, and I'm going to try it. Anything I can do to halt damping off problems is worth a shot.

Has anyone else tried this, (or even heard of it?)

Have not tried it but I will,Nice tip!:)

I'd question its effectiveness, G-V. Mold spores are everywhere, in the air as well as the soil. So if you kill the surface spores on the soiless mix, you're not really accomplishing anything.

Two things to try to control damping off. One is bottom watering (and don't overdo that). And two is to provide good ventilation, with a small fan or the like.

As to peat taking forever to absorb cold water, I slightly disagree. It takes forever plus three days. :-) Warm water should always be used if there's peat in the mix.

Another way to avoid damping off disease, I find, is to start seeds in pots of damp sterile perlite or vermiculite. Cover with a saucer and put in a warm place.

The seedlings come up in no time.

Dibber them into a tray of pasteurised compost (not sterilised, steam-pasteurised). Purchased sterile compost is okay.

Do not cover.

Then the only mould spores present will be air-borne.

This is infinitely better than sowing seed in a tray of compost, then putting a glass sheet or plastic bag over it - oft advocated by textbook authors. That way, almost _guarantees_ damping off disease!

A second idea, is to water seedlings with kelp (or seaweed extract) solution. It has anti-fungal properties and also nourishes the new plant.

I've never had damping off disease since I used method #1 - and have now thrown away my (useless) Cheshunt solution!

to prevent damping off, I water new seedlings with chamomile tea - 1 tea bag to a quart of water. It hasn't failed me yet.

I've used boiling water to "sprout" peat pellets in the past, didn't notice as they were any less prone to molds. They did pop up in less than a day, though.

Great idea, Kathleen!

I hear that an infusion of marestail, horsetail, etc (equisetum repens?) does the same...

I have an acre of it, so am lusting to try it - next season!

I hand-mill coarse sphagnum over the top of my sown seed trays; sphagnum also has very strong anti-fungal properties. It isn't dense enough to prevent light from reaching the seeds that require it for germination, and it provides a tiny bit of mulch to preserve surface moisture.

It is getting increasingly difficult to find, though, so when I run out, I will definitely use the chamomile tea!

My wife, who is a scientist, has questions about the efficacy of the boiling water idea.

First, she agrees that mold spores are literally everywhere, in the air, on every surface, etc.

Second, she mentions that different species of mold will be killed at different temperatures, some at temperatures above 100C (the boiling point of water).

Third, she mentions that as soon as you remove the water from the heat, and then pour it through much cooler air, you significantly reduce the temperature and any possible benefit this proceedure might bring.

Essentially, she says, you are partially sterilizing the heated water.

Imagine for a moment that you're a guy like me who thinks he has tons of cool creative ideas..., but that you're married to a woman who says..., "Well, that's lovely, but the second law of thermodynamics says that can't possibly work." It's a rather pragmatic life, but I love her anyway.

Adam.

Awww, Adam - you have our sympathies, although she must certainly keep you "down to earth"! Now you see the reason I posted this with a question mark. It wasn't my idea, and I thought I'd run it past the members here for their input. I may still try it, as a quasi-scientific "experiment" and just see if it makes any difference. (Of course, I'm really hoping this will be the year I have NO mold and/or damping off problems at all!)

Hey, GV..., I love a good cheap pun. Keep 'em coming ;~)

Adam.

I support Kathleens statement regarding the chamomile tea.
Since I've been using it I've had no damping off problems.

Paul

I just bought some chamomile tea yesterday to try to control damping off. I've been growing from seed for 60 years and haven't found the perfect solution, but hadn't tried chamomile tea. I tried course spagnum several times and gave up on that. I do keep two small fans running in my 10 x 14 greenhouse, all the time. Donna

I'm going to get in on this also!!!! I spray with the Sea Spray, diluted some, on the new surface of the seed packs, pots, or whatever and that has been a good method of preventing damping off! Elaine

I feel better after reading this! I remembered from a bacteriology class long ago, how difficult it really is to kill anything with water unless it's steam, with very high pressure for quite a few minutes. Seems to me that most commonly encountered organisms required as much as 30 minutes in a pressure cooker. Thus, the old autoclave units in doctor's offices. In one experiment, we washed our hands with warm soapy water, then looked at them with magnification. YUCK! So I never told my children to use warm water for cleansing, just because it felt good. And I have used soapy water to "set seeds in", as one prof called the process of lightly watering newly sown seeds, because the old style soaps could remain on and in the soil and deter growth of some trouble makers. With modern soaps, it probably would not be a good idea, with all the moisturizers and other additives. I do indeed understand the question mark, as this subject seems to be a constantly changing one.