[Stringbags]

I'm looking at under planting my sweetcorn with green manure rather than using bark chippings, has anyone any tips on the best to use? I have some mustard seed and alfalfa seed already in store and I think I have a packet of Phacelia somewhere, but I'm looking at a dual purpose , suppress the weeds and then either dig in when the sweetcorn are gone or leave over winter. This also gets me thinking what else could I underplant, sprouts, kale, runner beans, french beans, broad beans, cabbages? What do you think?

[Yorkie]

I would not do this, to be honest.  The GM will compete with the sweet corn for nutrients and water, and the sweet corn is a hungry plant so might not thrive as much as you would want.

For the same reasons I would not underplant with any other veggies.  Also, many of them have different growing conditions or timescales - you'd affect one or the other by harvesting / removing.

In parts of America they adopt the 3 sisters approach of growing corn, runner beans and another crop (can't remember which) but anyone who has tried it on here has always reported poor results.

I have grown squash around the outside of corn before.

[Trikidiki]

I under-planted broccoli one year with trefoil. Difficult to say if it helped or hindered the crop as I had no 'control' but they were ok. Problem was they didn't suppress the weed very well so I ended up with a bumper under-crop of weeds as well.

I think I'll leave green manures for the autumn/winter months when annual weeds won't be a problem.

[al78]

Clover and Trefoil seems to be frequently mentioned when it comes to intercropping. The clover will fix nitrogen into the soil which may benefit nitrogen-hungry crops such as brassicas. The foliage may help suppress annual weeds and when it has done its job can be dug into the ground to rot and produce organic material for the soil.