A few containers by a sunny door can make a useful first vegetable patch, even if the yard is only a balcony or a narrow step. Lettuce and radishes are good beginner crops because they do not need the deep space required by large fruiting plants. The first decision is not what to sow, but where the pots will get light.
Pick the Right Place
Choose a spot that receives several hours of direct sun and is easy to reach with a watering can. Use containers with drainage holes so excess water can escape, and set them where runoff will not create a problem. Leaf lettuce tolerates some light shade, while a brighter spot helps radishes develop well.
Use Loose Potting Mix
Fill the containers with potting mix rather than dense garden soil, which can compact in a pot and make drainage difficult. Sow lettuce seeds shallowly and thin crowded seedlings so the remaining plants have room to form leaves. Radishes grow quickly, but they still need enough space between plants to develop their roots.
Water and Sow in Stages
Check the mix with a finger and water when the surface begins to dry; containers can dry faster than a garden bed, especially in warm or windy weather. Rather than sowing every seed at once, plant a small new row of lettuce or radishes after the first has started growing. Staggered sowing spreads the harvest and gives you a chance to learn how your particular spot behaves.