[Broadhaven]

Can anyone tell me why my soil in some of my seed pots goes green ? Am I overwatering them? If so is there a usual rule as to when they need water? Sorrry if this sounds basic.

[Janeymiddlewife]

I'm no expert, but almost certainly overwatering - are you using rain or tapwater? Watering on top of the pots or from underneath, how much & how often?
someone else may have other ideas, I'm sure - 1 opinion would be soooo boring! 

[Yorkie]

It does rather sound as though you're overwatering, yes.

I tend to water the compost initially before sowing, then leave it until seeds are up.  If the pot is light when you lift it up, it needs watering.  Otherwise, it's probably ok

[Broadhaven]

Hi
I am using rain water and watering when they look dry, but not lifting them up. Should I scrap the green off or will it not harm them?

[Eatyourgreens]

When I bought a bag of compost early on in the year it was extremely heavy because it had been badly stored and become wet, even though it had dried out to near normal when I used it almost every pot full had developed a green slimy top regardless of how I watered. With no change in watering techniques things have gone back to normal with different supplies.

Bob

[Cazzy]

I'm sure this is caused by using rainwater, its to do with algae if I remember rightly and it causes no harm to the plants.

Maybe someone more experienced can confirm that though.

[blackbob]

I'm sure this is caused by using rainwater, its to do with algae if I remember rightly and it causes no harm to the plants.

Maybe someone more experienced can confirm that though.

yip its rainwater,shouldn't cause any probs with established plants,but dont use it on seedlings.

[canwickplot]

I've also found that rain water can have this effect, but I think it could also be affected by the lack of air circulation in the place where you are growing. This was the case with me this year.

[Kristen]

I get that too - but usually only on things that take ages to germinate.

Water seedlings with tap water, as others have said. Rainwater collects all sorts of muck on the way down, and running down the roof!, and tends to be more likely to cause damping off disease in seedlings.

I put a thin layer of vermiculite over my seeds (instead of sifting compost over them), that is much slower to turn green IME. (A small bag lasts me several seasons)

If I sow in a pot (rather than the propagator trays and clear plastic covers) I put the pot in a sealed plastic bag. The water that evaporates can't escape, so they don't need any more water until they germinate - open the bag once germination starts. For things that take ages to germinate I do get the pot out every couple of months and stand in some water until the pot is moist again (so I suppose it must eventually escape though my not-100%-sealed bags!)

[diggerjoe]

That explains it then. Being lazy I filled the can from the butt next to the green house rather than go down the garden to the outside tap. I have repotted all the peppers because the soil went green on top they are all growing well but it had me concerned as this is the first time it has happened.  

[Ivor Backache]

For goodness sake, rainwater sustains all the plants on the planet. Tap water is treated, clorinated, fluronated. There was recently a scare about a local reservoir and we had to boil our water.
Everyone must have noticed how plants respond to rainwater as opposed to a hosing down.
The 'green' are spores germinating. They are everywhere in the air and there is nothing you can do about them. Eventally they become moss and the worst that can happen is they seal the top of the soil and prevent water and air entering the soil. Normal potting on or planting out disrupts this.

[Kristen]

"rainwater sustains all the plants on the planet"

Indeed!, but generally without running down a roof that has collected all sorts of algae etc. and being stored in a water butts for all and sundry to multiply!

From the RHS website : "Use mains water if possible when irrigating seedlings grown in pots and trays"

[blackbob]

For goodness sake, rainwater sustains all the plants on the planet. Tap water is treated, clorinated, fluronated. There was recently a scare about a local reservoir and we had to boil our water.
Everyone must have noticed how plants respond to rainwater as opposed to a hosing down.
The 'green' are spores germinating. They are everywhere in the air and there is nothing you can do about them. Eventally they become moss and the worst that can happen is they seal the top of the soil and prevent water and air entering the soil. Normal potting on or planting out disrupts this.

for goodness sake i think you will find that your wrong on this one lol.

[DD.]

Don't forget blight! It brings that down on us as well.

[Ivor Backache]

FGS! Lets stick to the script. The question was 'Why soil in some of my pots go green'. Kristan then quotes RHS who are talking about damping off which is a totally different and far more serious issue. Furthermore he then highlights a sentence on tapwater out of a whole page to make his point.

There was another recent thread on water in a butt turning green. Don't recall anyone suggesting throw away the rainwater and fill up from the tap!

Broadhaven: You are doing nothing wrong. You can scrap off the green but when you pot on or plant out the green will be buried and gone for good.

FGS again! What has blight got to do with it. Might as well get a flame thrower.