Some gardens do need boron. It is one of the nutrients that leaches out readily. But I would suggest not putting it down if you've not done a soil test that indicates it is needed.

I speak from experience. I thought my celery seedlings would benefit from boron, so I added a very small amount to their drench feeding. Well, they are VERY unhappy campers. :((

So I'd be careful using boron in the garden without some sort of knowledge of what is, or is not, there already....

Edit: 3rd reading of this indicated I was not clear. The seedlings were still in pots, not planted. I do soil testing and add the correct amount to the gardens of boron and other micronutrients. But these seedlings had not been planted yet, so no soil test...