Seed sowing woes Solved

[richr]

To focus on your method, when you spray your seeds with distilled water - is that sterile?

The distilled water is sterile and it is the first thing I apply to seeds. Physan 20 (a fungicide) is sprayed on seeds to disinfect them. This was suggested by a professional, commercial cactus grower.

[rreynolds]

That all sounds incredibly complicated and for little return. I've been growing from seed for ever with no problems at all.

Clean pots, compost and vermiculite 50/50 (John Innes which I appreciate you don't have in USA). New plastic bags.

But then having sown the seed the first watering is by standing the pots in boiling water until it has soaked up. Leave to drain then into plastic bags and away you go. I am convinced the boiling water stops a lot of problems.

It is complicated, Herts Mike, but I wouldn't say it's for little return. I still grow a lot of the seedlings to maturity. i would just like to have fewer failures. I do what you do and more but still have issues with microorganisms. I am trying to create a nearly sterile environment so the seedlings can stay in the bags for up to a year. As it is, what I'm doing is apparently not enough or I would not get the mold and algae so soon in some of the bags. I would probably need to have a true clean room to avoid infections completely.

[rreynolds]

But then having sown the seed the first watering is by standing the pots in boiling water until it has soaked up.

Is this with plastic pots? I have some 2" BEF pots I bought 2nd hand and, as this method sounds appealing, I would rather not melt them when testing!

Yes, 2"x2" thick plastic pots which can handle the heat. I avoid the thin-wall black plastic greenhouse pots.

[rreynolds]

Wow, that's some process! Not sure what I'd suggest to change.

Are your pots plastic or earthenware? If the latter could there be residual spores deep in them which aren't killed in the microwave? I leave my sown pots to soak for a good length of time, so the seeds are fully wetted with the boiled chinosol infused water. Could there be something there?

My method is similar but simpler. I wet my soil (50-50 JI and volcanic grit)with tap water, in to the microwave until steam is coming off, let cool, put into well washed 2" sq plastic pots. Sow seeds and bottom water with weak Chinosol solution using boiled water. then into new bags and into propagator. I have each pot numbered with Brother tape label stuck on the outside of the pot so no need for labels in the soil at this stage. I've been doing this for quite some years, and mostly haven't had any problems, just occasionally a bit of algae a couple of years ago, which I put down to uneven soil sterilisation, but mostly OK. Nothing since then.

Hi Chris 43,

I use the thick plastic 2"x2"pots. You boil the water with Chinosol in it? What do you consider "weak" Chinosol? Is it still effective at higher dilution rates? Do you treat the seeds, too?

[rreynolds]

What do you put in your compost mix to provide nutrition for the seedlings? What light source and what intensity? I wonder if your conditions are favouring the algae and the moulds rather than the seedlings. I use similar methods to you, but without the precautions, except for using rainwater, watering with half-strength soluble cactus feed before sowing and a final spray with Chinosol. I find in the main that healthy seedlings grow fast enough to outcompete the moulds and algae.

I add a small amount of Dynagro 7-9-5 to the distilled water I soak the seeds with once they are sown and before they are bagged. I use a mix of 4000K and 6500K CFL bulbs. What kind of light would favor mold over seedlings? These are very bright. I got horrible infections when I used rainwater once. I'm sure it collects all manner of microorganisms as it runs off the roof and into the gutters.

[Herts Mike]

Just boiling water. Haven't used Chinosol or similar for years.

[rreynolds]

To focus on your method, when you spray your seeds with distilled water - is that sterile?

Mal H, yes it is sterile.

[Mal H]

OK. The insides of seeds are not sterile and there are studies proposing that seeds carry microbes from their environment that can facilitate growth on the substrates from which they grew/evolved. So, complete sterility is impossible but you know that I'm sure..

Great photography on your website!

[rreynolds]

OK. The insides of seeds are not sterile and there are studies proposing that seeds carry microbes from their environment that can facilitate growth on the substrates from which they grew/evolved. So, complete sterility is impossible but you know that I'm sure..

Great photography on your website!

Seeds not sterile on the inside? One more thing to worry about!

Thanks, Mal H.

[daydreamer]

In an amateur context you aren’t going to achieve sterility no matter what you do; at best you may reduce the numbers of microorganisms that make it into your baggie. So, aim for conditions that favour growth of your seedlings and discourage or at least don’t favour the moulds and algae. When they get large enough your seedlings will shrug off the moulds and algae.
Once you’ve sealed the bag the main things you can control are light and temperature. Seedlings are probably much fussier about temperature and light than algae and moulds - there’s evidence that too much light slows down seedlings and too high a temperature especially during the night may do too. I’d suggest you play around with your temperature regime (if possible) and light intensity and see if that improves things, eg cooler (especially at night) and not too bright during the day (so long as they don't etiolate).