Runner beans rotting again

[ameno]

This happening with different varieties. Best keep my own harvested dryed beans to sow next year from my garden. The ones that have germinated are still small and wispy. How on earth can something as robust as a bean go wrong in a packet?

They're not nearly as robust as you might think.
Bean seeds don't live all that long, anyway, and because of their large size and low oil content they are very sensitive to being stored in humid environments. They will absorb water from the air, and this makes them damp enough to allow bacteria or fungi to grow in them, which then kills them.
This absorbed moisture is usually not noticeable to human senses (they will still seem bone dry to us), but you can demonstrate its presence by putting the "dry" beans in a sealed jar or tub and putting that on a heat source. By the next day, you will usually find a noticeable amount of water condensed on the lid of the jar. This water all came out of the "dry" beans.

I find with beans it's best to pre-sprout them by putting them between sheets of damp kitchen roll in a sealed tub, then putting that somewhere warm (not too hot, mind, or you'll cook them). Good seeds should sprout within 2-4 days if you pre-soaked them, 4-6 days if you didn't. Bad seeds will start to go bad in the same time frame (they will discolour, become slimy with strange droplets of moisture on their surface, and will begin to smell). Good (or even decent) beans should not go bad that quickly, even if you accidentally kill them by allowing them to get too hot. Going bad quickly is a sure sign they were stored poorly (either by you, or by the retailer).

[Nicos]

Having had a good success with over 200 sown beans, we’ve come back to three plants with leaves All the rest have been munched by slugs or snails ( or maybe even birds?) whilst we’ve been away
If it’s not one thing it’s another
Interesting though to hear about quality of the beans though…a refund isn’t what we’re really wanting though is it when we’re trying to produce our own food.
Very disappointing for you marb.

[Marb67]

How old were the seeds and what conditions were they stored in? Airtight boxes and silica gel are wonderful things for seeds.
Was the compost sterilised? Ok, one would normally just stick them in the garden soil, but you never know.
How well were they watered|? Runner beans are one of the seeds that are prone to rotting if they are too wet.

Lastly, what did you do to annoy the gardening gods?

They were stored in the house in a plastic tub. The house gets quite humid over winter (old house) and even with a dehumidifier its hard to keep the levels down enough.

I never sterilise compost. Why would you ?

Damp compost enough to germinate but no more watering. Also the temp is high enough for germination.

The seed packets are well in date till 2025.

[Nicos]

No idea what went wrong marb, but plastic tubs might be a contributing factor. Things sweat inside. Try paper bags this winter - I think that may help .

[ameno]

Plastic tubs are better than paper bags, especially in a damp house.
I've found the best way to store beans is in a plastic tub with some sachets of silica gel. In paper bags they just absorb water from the air over winter and go bad.

[Jungle Jane]

Damp compost enough to germinate but no more watering. Also the temp is high enough for germination.

When you see the compost raise in the pot/movement of compost as the bean is germinating,give a little extra water,not a soaking just enough to stop the seed drying out as it’s root is growing. Also the top of the compost hardens,that little extra water will soften it for the seedling to push through easier. I always have to do a second watering like this. Your seed could be germinating but dying as it’s drying out?
edit - you don’t have to wait for the movement of compost,you can feel the weight of the pots to feel if they are lighter & water would be needed.

[Marb67]

When you see the compost raise in the pot/movement of compost as the bean is germinating,give a little extra water,not a soaking just enough to stop the seed drying out as it’s root is growing. Also the top of the compost hardens,that little extra water will soften it for the seedling to push through easier. I always have to do a second watering like this. Your seed could be germinating but dying as it’s drying out?
edit - you don’t have to wait for the movement of compost,you can feel the weight of the pots to feel if they are lighter & water would be needed.

Yes I have always kept them moist enough. They just seem to stop growing. Even the ones germinated weeks ago are thin and wispy. Perhaps if I plant them out they will thicken up.

[Jungle Jane]

Yes I would plant them out & protect from snails if you can,when we water out plants it must alert snails to the wet areas,I often add a bit of water at the back of the bed to try & keep them over there,like a distraction