Author Topic: Suggested Damping Off Solution.  (Read 3143 times)

ed dibbles

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Suggested Damping Off Solution.
« on: February 13, 2018, 09:07:21 »
This tip from a tropical gardening site using boiling water as a pre sowing compost steriliser.

To save you reading the whole page here is the relevant extract.......

Before planting I like to sterilize the compost. This is to kill off any fungal spores that may wish to attack your babies as they emerge. My preferred method is as follows:

Fill the clean flower pots with a multi-purpose compost (new shop bought stuff, don't use any old rubbish left over from last year!). I like to use boiling water to sterilize the compost surface. Fill a small (pint sized) watering can with a fine rose attached, with boiling water. Water this onto the compost. Using a fine rose prevents an uneven surface. A small watering can prevents you pouring boiling water all over the kitchen floor or onto your legs.

If you do this an hour or so before planting, the seeds will benefit from having a nice warm pot of compost. The compost will also have drained any excess water and be at just the right level of moisture. Pop the seeds in evenly and not too deep.

The writer is discussing canna but I have tried it with a few pots of fine seed (petunia etc) and no sign of damping off at all. :icon_cheers:

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Suggested Damping Off Solution.
« on: February 13, 2018, 09:07:21 »


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Re: Suggested Damping Off Solution.
« Reply #1 on: February 13, 2018, 11:28:34 »
I like to sterilise seed compost in the microwave so I can re-use last years (I call this careful not mean - none of the compost suppliers guarantees sterility anyway).

20 minutes for 6 litres is plenty - suitable containers are available for 1, though a cardboard box is perfect as a one time container (mainly because the compost has to be fairly damp or else it will dry out and be a pain to re-hydrate).

The hardest part is making absolutely sure no friends (like earthworms and centipedes) are in the batch - but the same goes for boiling water.

NB. seasonal advice - if you are chitting seeds use a nearly-shut microwavable box (cleaned readymeal boxes are the best size and shape) and microwave the whole setup - box, platform (cannibalised from older boxes), paper and water for 1min before sowing the seed (after it gets back to hand heat). It's best to poke holes or slits in the paper first or it may lift off and get stuck to the lid. Seeds will always carry their own moulds, but it still helps to have everything else sterile.

With a microholding you always get too much or bugger-all. (I'm fed up calling it an allotment garden - it just encourages the tidy-police).

The simple/complex split is more & more important: Simple fertilisers Poor, complex ones Good. Simple (old) poisons predictable, others (new) the opposite.


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Re: Suggested Damping Off Solution.
« Reply #2 on: February 14, 2018, 12:35:07 »
I don't want to put a dampener on the idea, but I have always thought the biggest risk was watering with water that carries the infection. The problem then with sterile media is that whatever you add is free to multiply without competition. Some suggest, and I concur, that one advantage of homemade compost or sowing in soil is that there is such a good mix of microorganisms that no one thing is likely to go rampant. I've rarely seen anything damping off myself.  Just an idea from a different angle.

Tee Gee

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Re: Suggested Damping Off Solution.
« Reply #3 on: February 14, 2018, 14:45:22 »
Strange how we have all got different opinions on this subject including myself!

That's not to say anyone is wrong here as all the suggestions are probabilities!

My call on it is this:

Damping off takes place at the point where the stem emerges from the compost and I put this down to cold compost at this point, i.e. the surface of the compost!

When the surface of the compost gets wet the temperature drops at this point creating extremes of temperature just above and below the compost surface, and it is these extremes that are in my opinion the main cause of "Damping Off"

My solution is not to wet the top of the compost but water from below or mist spray.

In this way the compost remains relatively dry and is around the same as the ambient temperature.

I look at it this way:  In nature the cotyledon leaves act as an umbrella and keeps excess moisture away from the stem at soil level, hence my methods.

BTW one should always practice good general hygiene such as using clean water and sterile compost.