Did you feed them any of that Jacks 20-20-20 already?

Nutrients lower the ph.

Most garden soils are generally buffered to a near 6.0 ph. (too low) I'd try an indoor mix next time.

From Scotts Miracle-Gro soils:

"�When planting annuals, make sure to properly amend the native soil in your garden. We recommend using an all-in-one garden soil like Miracle-Gro® Premium Garden Soil Plus� 0.15-0.05-0.10 that combines organic matter, sphagnum peat moss, and Miracle-Gro Plant Food all in one bag.[B] And remember that container plants need potting mix, like Miracle-Gro® Moisture Control® Premium Potting Mix 0.18 - 0.10 - 0.10, not garden soil"