This season I went a little gung ho with the tomato plants, but I've been loving every tasty moment. One reason I love them so much this year is that I've been altering their acidity levels to make sweet tasty treats. If MacGyver had a garden...
... he would have done the same thing!
This season I've been following a simple routine. I fertilize with a natural fertilizer once a week and then on Fridays I sprinkle baking soda on the top of the soil surrounding the plant (making sure not to get any on the plant itself).
Although it seems silly, this simple garden trick really works. The baking soda absorbs into the soil and lowers its acidity levels giving you tomatoes that are more sweet than tart. Although I haven't done this with every plant on my patio, having a few extra sweet nuggets to mix into a fresh tomato salad has been a wonderful discovery!
Related: Have Extra Tomatoes? Make Cobbler!
(Image: Sarah Rae Trover)
Straw Mat from The ...

In a pot, which you seem to have. This trick might work, because you would replace the soil every year. Otherwise, never do this to your soil. Sodium bicarb messes with the healthy soil balance by salting the soil and killing beneficial organisms and plants (it's used as a natural way to kill crab grass.)
was just about to say the same thing. from the soil ecology (sustainability) point of view, not a good idea.
Yeah, messing with the ph of soil in a plot isn't wise, especially if you plan to rotate your crops.
you would be better off using it as a foliar spray