fixing a low P problem is really straightforward; get some basic fertilizer like miracle grow that's 15-30-15, or even the Schultz Expert Gardener bloom booster, it's 10-60-10, and then use it acc'dg to pkg directions. Since it's water soluble it will soak right in and be immediately available. It will definitely help your blooms and make things smell better too! Used in moderation it won't damage your soil life, either.
For full-on organic gardening, you want to mix in ground bone meal when you do your soil prior to planting, so it's a bit late to do that now. In this form the P is insoluble, so you feed your microherd and they'll go to work freeing it up for your girls.