Too late to lime?...and pH

[Gordonmull]

Most of my onion seedlings are up and I'm planning to plant them out under cloche in mid march. I've since realised that my soil is acid and onions don't like that. Is it too late to add lime?

The soil is heavy clay that I am amending with civic amenity centre compost.

I bought one of those wilkos pH and moisture meters but the pH has no numbers on the scale. All I can say is it's about halfway along the red part of it. I'm planning to get an aggregate sample tonight, dry the soil, homogenise it, fill it to field capacity with rain water and let it drain before using an aquarium pH test kit to get the pore water pH. Does this sound like a feasable approach?

But, crucially, is it too late to amend soil pH or do I need to think of another solution?

[Gordonmull]

[shirlton]

I have just looked it up for you and it says to lime in the autumn and let it get into the soil.However I do put lime around the brassicas when planting out but put it approx 5" away from the stem.

[goodlife]

It's still ok..I do mine as well after planting..but its only light 'dusting'..not full whack and I water it in as well.

[Gordonmull]

Thanks folks.  I've seen advice to lime in autumn but I didn't know what the consequences of doing it now would be. I take it the risks I would run would be burnt plants roots if threw a full dose on there at this time? My sample is drying in the oven just now, so I'll report back when I've got an actual figure. Here's hoping that probe is lying!

[Digeroo]

Is it possible to add something rather gentler such as bone meal, wood ash or egg shells?   

[Gordonmull]

I've got bonemeal that I inherited with the shed and the blood, fish and bone that I was intending to dig in as a general fertilizer. I can keep throwing eggshells on but won't have enough to treat about 6 square meters. Any idea what sort of application rate I'd be looking at for the bonemeal? Just the as per label instructions, or would I be better with the BFB?

I also inherited a soil testing kit that I had completely forgotten about. It belonged to my wife's Grandfather who passed away about 15 years ago, so I'm not too hopeful about the quality of the reagents. I've given it a whirl all the same, waiting for the soil to settle in the tube.

[winecap]

Dr Hessayon (aka vegetable expert) says on page 5 to lime the freshly dug surface (presumably in Autumn) but adds that if you dig in manure you should postpone liming until February. I guess that means that now is fine.
I confess though that a couple of years ago I ended up digging, liming, raking and planting all on the same day in May as the plants were ready to go in the ground and didn't look like they would wait any longer. They turned out great, but I guess I only ever use a cautious amount of lime. 

[goodlife]

Bone meal is classified as a fertilizer..if it has any effect to PH, it is so minimal that it doesn't really benefit.
Ash does have some effect, but it is very soluble and has also fertilizer effect..it is quickly washed down by rain, so again effect is minimal...and BFB is fertilizer..both bone meal and BFB meal are better thought as 'neutral' to soil PH.
Egg shells..you would need a lot to have any effect and it is veery slow releasing..so again..it would not give much effect for this coming growing season.

[Ellen K]

I've read that onions do best in acid soil so I wouldn't lime onions.

I would argue that general soil improvement (like chucking compost on) is the best way to go and liming is for brassicas where raising the pH is supposed to make conditions unfavourable for club root. 

So liming schmining - spend your money on a sack of tomato food and give that to your onions.  Works for me!

[Gordonmull]

Well three days of waiting later and the soil finally settled in the pH tube. It looks like it's somewhere about 6.5-ish so I'm relieved. That meter's going back to Wilkos and they can keep it. pH scale with no numbers indeed.

Anyroads, thanks for your input folks. No lime required it seems. Phew!