Do soil samples expire?

[Cows 'n grass]

I have a heap of samples that I took 3/4 weeks ago and haven't sent off yet. I rang a rep this morning to ask for them to be collected and they they need to be analysed within a couple of days of digging. They are in sealed plastic bags and I'm only looking for basic pH, P and K.

Can this be true? What will have changed with soil in a bag Vs soil in the ground?

 

[Princess Pooper]

I've often wondered this as I have also sent off 'old' samples before. Sure, deep N sampling has to be very fresh and, most importantly, kept cold, but I've never been told that the PK pH samples will 'alter'. Also says nothing in any sampling protocols.

 

[deleted user 837354]

Just send them.

I asked at the lab if aged or very wet/very dry samples mattered. They were nearly mystified as to why I would ask. All samples are oven dried and ground to dust before being subjected to the tests using ICMS. Wont make any odds.

 

[PSQ]

I don't know if they 'expire', but the soil will certainly 'respire'.

If moist and in a sealed warm bag, I would imagine there could potentially be issues with anaerobic bacteria lowering the pH ???
If the samples are dry they should be ok.

 

[Cows 'n grass]

I don't know if they 'expire', but the soil will certainly 'respire'.

If moist and in a sealed warm bag, I would imagine there could potentially be issues with anaerobic bacteria lowering the pH ???
If the samples are dry they should be ok.

Excess moisture definitely hasn't been an issue with us this year.

A slightly lower than real pH wouldn't hurt either because I'm trying to persuade the land owner and NE the need for lime.