Fertilizer Ice Cubes
Your potted plants may think you're cool, if you fertilize them with ice cubes.
Put your favorite Liquid Plant Food in ice cube trays, reserved and marked for this purpose with a felt-tipped pen. Then slip the trays into a sealed plastic bag to contain any spillage. Place the trays in your freezer until the fertilizer is frozen. Then move the Fertilizer Ice Cubes to a second plastic bag or freezer box(es) conspicuously marked and reserved for "Plant Food".
The ice cubes melt slowly, allowing potting soil to absorb the liquid without draining out the bottom, or spilling it in the pouring process. Do not allow the ice cubes to touch those plants that are cold-sensitive.
from the staff of Garden Grapevine