Harden Off Seedlings
If you started annual or perennial seeds indoors, begin to harden them off so they're ready for life outside. Do this by gradually exposing them to longer periods of sun and weather by first placing them in a coldframe or covered area, such as a porch, for a week to ten days and then moving them into the garden.
Watch for Aphids
Keep a close eye on tender new growth of perennials and newly transplanted annuals to ensure they are not plagued by aphids. If you do find these pests, wash them away with a gentle spray of water from the garden hose.
Before you forget useful information, take note of the performance of spring-flowering bulbs by recording which met expectations and which didn't live up to their hype. Also take time to consider if some bulbs need lifting and dividing, and if there are additional areas in the garden that might be planted with blubs in the coming months.
The best time to divide cannas is after they've sprouted but before they've grown more than an inch or two. To divide, dig up the whole clump, gently brush or wash away the soil so you can see the rhizome, and then cut the rhizome so there are two or three healthy sprouts on each section. Replant 8 to 12 inches apart, and keep the cannas well watered until they are reestablished.
Thin Root Crops
If you haven't already done so, thin radishes, carrots, onions, beets, turnips, and Swiss chard so you can get three fingers between each plant. With this much space, they'll have plenty of room to grow. Beets and chard, which grow from compound seeds that produce multiple plants, are especially prone to overcrowding.