Depends on the size of the container, but you don't want to overcrowd and you also don't want the container to look sparse.
- Small herbs (like basil, parsley): 2–3 plants in a 10–12" pot
- Lettuce or greens: 2–4 plants in a 12–14" pot
- Tomatoes or peppers: 1 plant per 5-gallon container. Don't attempt to plant two or more tomatoes in any pot - they simply won't thrive.
- Root veggies (carrots, radishes): Several, spaced according to seed packet directions
- Flowers (like petunias or marigolds): 3–5 in a 12–14" pot for a full look (see tip below). You can always plant a single plant in one smaller pot and have a few smaller pots clustered together for a lush look.
Here’s a specific planting chart for common vegetables and herbs grown in containers, including recommended pot sizes and spacing:
Container Vegetable & Herb Planting Chart
Container Flower Planting Chart