Avoiding Root Disturbance when planting out Beans

[George the Pigman]

Over the last few years I've struggling getting runner and climbing French beans to survive when planting out. Often only half of them survive and the others clearly have a setback with yellowing leaves. I usually grow them in RootTrainers to avoid root disturbance as I know they don't like it and am careful about planting them out well after the risk of frost in my area and always water them well after planting.
I've tried many times sowing them direct in good quality soil in raised beds but they never come up (?pests) even though the soil temperature is OK.
I am thinking of trying sowing them in a biodegradable pot then planting this in the soil but looking at the time for some of the products they are made of to degrade they degrade fairly slowly i.e. in a period of months. I would want the roots to spread out of the pot in a period of weeks not months otherwise growth would be restricted.
Anyone had any experience of using these for beans (or peas) or any other suggestions.

[JanG]

I'm surprised that you have such problems when planting out beans from roottrainers. I have grown them this way for many years, more recently in Containerwise deep cells but much the same thing.

I'm wondering whether the problem is something other than root disturbance. How far advanced are the beans when you plant them out? Have they been in their cells for too long and formed too congested a root system?
Or could you be over-watering? Yellowing leaves sometimes suggest over-watering and, although runner beans like a lot of water, French beans don't like to be too saturated.
Or too rich a soil? I've discovered over the years that French beans don't need a heavily enriched soil and think I might have lost some due to too much manure in the soil.

Sorry, I have no experience of using biodegradable pots but do feel that they shouldn't be necessary and that the problem is more likely to lie elsewhere.

[galina]

I agree with JanG.  My usual problem is that slugs love newly planted out French beans.  But you see their tell tale slimy trails.  A cut off plastic bottle on top, until the plant is big enough to withstand slugs fixes that.  Another predator are voles, who nip off the stems of more mature plants even.  If you only have so few surviving, I would suggest frost (which is not the culprit you say), slugs or voles. Could also be chickens who nibble at plants, if you have those.  I guess netting helps against chickens. 

[George the Pigman]

Thank you both for your comments. The  bean plants (Runner and French climbing) usually start to show yellowing leaves within a few days of being planted. Some recover and throw up fresh leaves. Others wither and die. No evidence of any pest damage.
I've grown peas and broad beans in RootTrainers for years for planting out and not really had this problem.
The recent ones I planted had good root systems but were not root bound. The soil is in a raised bed enriched with  good quality compost.
Looked up something about transplant problems with beans and research apparently suggests it's to do with damage to special root hairs that link in with the Nitrogen fixing bacteria many legumes have.

[JanG]

Given that you, Galina and I, and many others, have happily transplanted beans for decades without this trouble, I would still suspect over-rich soil or watering before root disturbance. But good luck with biodegradable pots if you decide to try them out. I imagine they're not cheap so you could always try a few and compare results with those you simply transplant from roottrainers.

[galina]

The ultimate biodegradable pots without the cost is of course making your own pots from newspaper.  Doesn't have the big problem that roots can't so easily break through, although at planting out time, make sure the rim of the paper pot is under the soil or tear it off if it is not.  No need at all to buy the formers, I use small bottles of the right size to make my own, when I use them.  In the video, the lady uses a glass, whatever provides the right size pot you need.  They don't hold together on their own very well, so I place several of them into one of those plastic fruit containers from the supermarket.  The ones that have holes in the base already. 

Here is the video  https://www.youtube.com/watch?v=b_x6OSKQr4o&t=117s

These are the supermarket punnets that I place my paper pots in  https://www.shopler.co.uk/blog/why-fruit-punnets-are-the-supermarkets-bestselling-packaging/?srsltid=AfmBOop4xOvX3eqQ3YBPV2GBunKged1WZXImGqYdf-4NlWe5vN97ptyo

[Multiveg]

I've been using loo roll inners for beans and sweetcorn..

[Paulh]

I used pots made from newspaper very successfully for peas and beans for about 15 years until a few years ago. I don't use them now as the new composts seem to be either very wet or very dry in them.

Everyone seems to be having difficulty getting things to germinate, but particularly beans. I suspect I am sowing beans a little too early. Some people are now chitting their seeds before sowing.

I now use small cells (12 to a half tray) for sowing beans as I think that avoids the compost getting too wet. When (if) they germinate, I transplant them at past the first true leaf stage (roots just showing through the bottom) into larger cells (6 to a half tray). When they are nice plants, (and again roots showing through bottom) I set them out. Plant slightly deep to cover the root ball, which should be a good block in the cell.

They sit for a while as the roots move out, then are off up the canes.

Planting out at this size makes them less attractive to slugs and snails.

Last year a plotholder looking for plants when her sowings all failed found a solitary tray of strips of Cosse Violette at the garden centre - dried out, battered plants - and was pretty well given it for free. I took a couple of strips, as I have not grown them before and like trying different varieties. I watered them, cut the dead bits off and later separated out the plants and potted them up. I ended up with six plants that flourished and cropped heavily. I've grown them from seed this year (the latest I sowed and 11/12 germinated - see earlier comments!).

So in my experience, French beans (and runners) are pretty tough but plant them out as large plants.