Following the directions on the seed packets, sow seeds of radishes and greens in one box, beets and carrots in the other. Radishes are ready to harvest about 28 days after germination; baby greens (lettuce, spinach, mesclun), in 30 days; beets, in 55 days; baby carrots, in 70 days.
You don't wash seeds out of the soil. Keep soil evenly moist, and watch for seeds to germinate.
Watch Your Seedlings Grow
Seedlings will come up thickly; thin them the first time to stand 1 inch apart. You can either pluck them out individually or use scissors to snip seedlings at the soil surface. (Eat the thinnings of greens and beet tops -- your first unofficial harvest!) Thin the carrots and beets again when they've doubled in size; ultimately they should stand 2 to 3 inches apart.
Sow Some More
As your harvest of greens and radishes makes room in that container, prepare to grow another round. Work an inch of compost into the empty spots and sow more seed.
Maintaining Your Window Box Veggie Garden
If you have enough space, add containers for other salad favorites, such as tomatoes and cucumbers. (They need larger pots.)
For color and spicy flavor, sow a few nasturtium seeds in your containers. The flowers are beautiful, fragrant, and tasty in a salad!