I'm inclined not to believe that trellising has anything to do with productivity. Might be weather, but I'd rather just call it bad luck. No question that you should let them run over the sides and spread where they want. Vining squash really doesn't care what it's vining on top of, or what it's hanging on to. .Allowing it to spread just increases the amount of sunlight it can intercept.

I was thinking the same as vgkg - and was just reading an article about things that don't do very well in raised beds - squashes being one because they tend to need a lot of space/soil for their root systems.

On the surface, the comment re: anchor roots makes sense. But, the years I grow the squash and let them run on the ground, I put landscape fabric underneath -- about 2 foot lenght of soil in which the plant is planted, landscape fabric rolled out to about an 8 foot run, over which the vines sprawl. I did this to help keep the weeds down (when I rotated locations, I just picked up the landscape fabric and moved it). Because of the landscape fabric, the vines never put down any additional roots along the length of the run, so that theory wouldn't explain the much higher yield in my case.

Hmmm....I'm in central Indiana, and this is the absolute worst year ever for my Waltham butternut squash. I've been growing it up the side of a swing set that's covered with concrete reinforcing wire. One year it grew up over the top and down into the garden! I think I got 40 squash that year. But.....this year I only have 1 small squash and it hasn't grown much. It had no female blossoms until now........mid August. So, I have to agree in part with Daninthedirt about the weather. It's been just too hot this year. the concept that if they grow on the ground, that they put down more roots is interesting. I went to my swingset method, which got rid of many pests on the ground. I guess you could plant them in a raised bed, but put some kind of high trellis next to the bed. I did that one year with beans, and it worked well. What kind of raised beds are you using? But I really would consider the climate this year (and maybe from now on), as to why your squash didn't do well this year. We LOVE eating the squash in winter, so we're really bummed out. Good luck!

I usually let it sprawl around but have never noticed secondary roots. The tendrils do tend to grab onto any low growing plant material, Mine have been slow to get going but mostly because my soil is really awful and has not had enough amendments for quite a long time (since I got burned with a bad batch of manure still affected with long lasting pyralid herbicides). The problem of getting enough manure has been an ongoing one for me which no amount of home-made compost or granular fertilisers have fixed...not without spendy bought in additions of guaranteed (herbicide free) animal fertilisers. Last year of vegetable growing for me, in fact, as the results no longer justify the time and effort expended.

So sorry HU 618169007! :(