Are they tiny, or good sized transplants? Do you have another area you could spread them around in? If not, I would just get them in the ground in that 4x4, and worry about thinning them out next year... Happy Gardening!
I put 25 in a 4x8 foot bed last year, and that seemed about right. They sent out runners all over the place and are now putting out leaves for (hopefully) my first crop.
I think 50 will be a few too many for a 4x4 bed, but if that's all you have then just plant them and see what happens.
They are just the bags of "bulbs"...I have 8 4x4ft raised beds but I could always get the hubby to crank out a 4x8 for me just for the strawberries. I was thinking of doing a pyramid too but that seems like a lot of trouble.
We have one of those green well head boxes out in the middle of our front yard which is an eye sore. Last week Teresa had me to make a 4x4 box from a couple of 2X8's I had laying around and I put it around the thing. Then I made up a 2x2 box made from a 2x4 and place it over the green thing (cover). It fit perfectly so that if necessary we can still remove the cover without having to destroy the bed. Then she made up some of the Square Foot Gardeners soil, filled it in around the 20" or so area and then planted 18 strawberry plants. It still looks like $%#& but at least we'll have something tasty come from it now.
I knew someone with a pyramid once... let's just say that the top two tiers of three dried out every day in under a day in the damp PNW and the only strawberries came from ground level. They just put in the regular dirt from the ground, tiers probably need garden soil/potting mix that retains water better .
I put plants about 12 inches apart from each other in all directions to make a patch of strawberry field. They usually send 3-4 runners out each, so they multiply fast.
But I don't recommend trying to squeeze all 50 in there. They'll be too crowded and won't do well.
Assuming what you got are Everbearers (which are ideal for raised beds), you could get 16 in a 4x4 bed. They need to be a foot apart in rows (or in this case, 1 per square foot). They're going to make runners and in a raised bed you don't want to let them go crazy. Pinch all runners and blooms this spring, then as summer goes on you can allow up to 4 runners to develop per mother plant for best results. Everbearers give you a late summer crop in their first year and will continue to produce right up until first frost. They will make additional crowns on the mother plant each year. Good production and larger sized berries are therefore better on the older mothers. After 4 or 5 years they will peter out though and need to be replaced, so you can keep a rotation going with the healthy runners.