Skip the exotics and fragiles and head for hard-working standards. Overgrown pansies are incredibly forgiving, once released from their container prisons and watered well with a weak, warm fertilizer solution. Towering petunias can be pinched back and reappear looking remarkably shrub-like and vigorous. Marigolds that are fading in a six-pack can be resurrected by a bit of judicious deadheading. Your June may not be as colorful as you'd hoped, but July will not disappoint.
Vegetables are another story.
Many of them take all summer for their produce to mature, and a two-week delay may mean there is nothing harvestable. The trick is to find edibles that produce vegetables like annuals produce flowers, in other words, all summer long. Squash and cukes are two prime examples. If you can't find any at the nursery, ask friends and co-workers if they have any in pots that they did not have the room to transplant but can't bear to throw away. Pinch off any blossoms, feed, water and transplant.