I have grown sainfoin in my deer food plots. Sainfoin is very similar to alfalfa in that it takes some time to get established. Both have deep tap roots. It is equally, drought and heat tolerant (very heat tolerant). The biggest plus of sainfoin over alfalfa is that it doesn't get stemmy and un-palatable once it starts to mature. Also when everything has started to turn in mid-summer, sainfoin shines compared to the other legumes. Doesn't dry up and deer love it. Alfalfa usually won’t dry up either but it gets real stemmy, and the deer put it pretty low on the preference list.
Now for the negative. Sainfoin is not very browse tolerant. It's considered a single cut hay in most applications. This is because it just doesn't bounce back after being consistently grazed. This can lead to weed issues, as lack of regrowth really allows for weeds to "fill in" the plot. So if you are in an heavily grazed area or already have lots of weeds, I'd suggest red clover, or even alfalfa. Sainfoin will most likely disappoint if this is the case.
The niche for sainfoin is that it is a big draw for deer especially when everything else is dry, but this is also its downfall. If you have good moisture I would stick with clovers. If you do plant, make sure your soil is well drained and in good shape. Also make sure you get the newest variety "Delaney Sainfoin" as it’s supposed to be more of a double cut variety, but I have not planted that type personally.
