Read your post quickly Edd. Thought it said spinach (boiled)
I've never tried it but in theory anything will grow if the pot is big enough and the compost, feeding and watering are right.
There is no info on your profile TheSeed. Can you explain who 'we' refers to. Where are you based, who are your customers and what are the items being sent out to them?
Start a new thread with a photo Mimie, things will get confused on this thread.
If it's not spinach it's a very close relative
I would pot it on and plant it out when it's a bit bigger. Keep it in a shady spot where you can keep an eye on it and water as required
The idea that all wildflowers need nutrient poor soil is a myth. Some might do well on it but they're just plants, all with different needs.
I have a good collection of native plants. I love them and all the wildlife they bring in..
Good to see another convert NM
Cuckoo spit. Have a poke inside tomorrow and see if there's a little green insect inside.A froghopper
Perovskia looks likely