watering seedlings from below.

[brownfingers]

Do you just sit them in water until compost soaks up as much as it can, then remove and allow to drain, or do you just give them 5, 10, 20 minutes each and take them out?

[NoTWHaTiTWaSNT]

Some answers to your question in this thread

http://www.growfruitandveg.co.uk/gra...ver_78775.html

[brownfingers]

Cheers that man.
Just one extra thing: I sow singly into deep pots. I reckon letting the pot stand until the surface is wet would be too much. On the other hand, not giving it long enough may not be enough to get water up to a young seedlings roots. Life is seldom simple is it?

[Potstubsdustbins]

Don't pot on into much larger pots take it a step at a time i.e. from 3" to 4" this way the roots will grow better and they will never be to far away from the water source.

One of the ideas about watering from the bottom is not to get the surface wet, this helps prevent damping off.

One way of judging is by the weight of the pot, light when dry, heavy when wet.

If some kind person could put up a link to 2Sheds watering video that would be a great help here.

[Kristen]

Just one extra thing: I sow singly into deep pots. I reckon letting the pot stand until the surface is wet would be too much. On the other hand, not giving it long enough may not be enough to get water up to a young seedlings roots.

I don't hold with standing a seed tray in water, after sowing the seeds. Saturates the soil and takes all the air out of it - and, being only seeds, its not like they are plants with loads of roots to drink all the excess water - that water is going to just sit there, until it evaporates from the surface.

My approach is to get the moisture content of the seed sowing compost right first, then fill the trays with it, sow the seeds, and then put the tray in a plastic zip-lock bag (or use one of those clear plastic dome lids, if it has one instead) and leave it until it germinates. The water in the tray can't go anywhere, other than to evaporate, condense on the plastic and run back into the container

As Pots said, putting a tiny seed / plant in a big pot means that the plant will either drown (i.e. very difficult to get the watering right, because the plant can't drink the amount of water in the large pot easily), or its roots will grow straight to the side of the pot, rather than filling the centre part. Whereas if you start with a small pot, and pot on 1.5" - 2" additional diameter each time, then the plant will fill the edge of each pot with roots, and by the time you get to a large pot the whole rootball will be solid with roots.

[Kristen]

My approach is to get the moisture content of the seed sowing compost right first

Sorry, forgot to describe that bit.

Squeeze a ball of compost in your hand (actually it will make a shape more like a sausage than a ball). if water runs out you've got too much water. The sausage should stick together and if you snap it in half it should break cleanly - not all crumble to bits. If it crumbles to bits you haven't got enough water.

So basically it should be on the point of water running out, when you squeeze it, but not so wet that water actually runs out.

[Two_Sheds]

I reckon letting the pot stand until the surface is wet would be too much.

you're right: the surface soil shouldn't be wet, it should be dry. You want the moisture where the roots are, and you don't want the roots on the surface

I don't water the surface on the lotty either: I sink flower buckets in the ground and water into them. Straight to the roots, not left to evaporate on the surface. If you water the surface you'll germinate a load of weed seeds too, just like the rain does

not giving it long enough may not be enough to get water up to a young seedlings roots.

You'd be surprised. Put a dry pot into a clear saucer (pyrex dish or an old hummous tub) and you can literally see the water being sucked up by the compost.

it's a good thing to encourage the plant to send its roots down to the bottom of the pot. They'll be better survivors out on the plot, where they sink their roots down to find groundwater.
If a plant has shallow roots near the surface, it will dry out much quicker.

[brownfingers]

One thing I found by sowing in deep pots, (those plastic vending cups), was that the seedlings threw one long root straight to the bottom rather than branching out. That can't be good can it?

K: The pots only have a small diameter, but they are deep. Do you think this is a bad way of doing it?

[MrsCordial]

I had real problems with transplanting things that hadn't grown enough root. I was transplanting because things were leggy (because they hadn't got enough light because they were inside because I sowed far too early!), instead of waiting til the roots were really well developed. When a seedling has developed lots of root the whole 'thing' inside the pot holds together much better when you pot-on or plant out. Slightly off-topic but just wanted to mention why getting the roots right matters so much

[Kristen]

One thing I found by sowing in deep pots, (those plastic vending cups), was that the seedlings threw one long root straight to the bottom rather than branching out. That can't be good can it?

I think that depends on what it is. A Parsnip, for example does exactly that - sends down a tap root. It does this surprisingly early - within a month of sowing it is likely to be a foot long, and that that time the "top" will probably only have its first, tiny, set of true leaves. Plants with a tap root like that (including Carrots) are difficult / impossible to transplant, and are better sown direct.

Other things, such as Sweetcorn, are very shallow rooting. However, if you start them off in a pot they will fill the pot with roots, and quite possibly give the appearance of sending a main root downwards first,. Leave them a bit longer and there will be a mass of roots in the pot, and no evidence of a single tap-root coiled up around the bottom (leave them too long and there will be masses of roots coiled up around the bottom, but no single such coiled tap-root)

I don't use vending cups; no doubting that they are cheap / free / recycled etc but I prefer something stiffer. When I get things out of vending cups, or the really thin module "tray liners", the rootball gets squished and pushed just to get the plant out and I think that disturbs the roots during the process. (Much less so with a vending cup and cheap thing tray-liners, but with a decent stiff pot I can just knock the side of the [upside down] pot firmly on a table etc. and the plant falls straight out - no root disturbance)

Vending cups don't have the "profile" (diameter to height) of regular pots. I don't know if regular pot shapes are scientifically proven to be the optimum shape (and they do come in a number of different ratios), but either way there are no pots that I know of which are as thin as vending cups. For something, like a runner bean, which is only going to be in the pot for 2 or 3 weeks, and doesn't much mine if the roots are disturbed during planting, I don't suppose it will make any odds.