Container Gardening FAQs - Your Complete Guide

Getting Started with Container Gardening

Container gardening is one of the easiest ways to grow fresh produce without a traditional garden bed. Whether you’re working with a balcony, patio, or sunny windowsill, this section covers the basics to help you start successfully.

What is container gardening?

Container gardening is growing plants in gardening containers — such as garden boxes, pots, planting bags, or self-watering planters — instead of in-ground garden beds. It’s ideal for balconies, patios, rooftops, and even indoor spaces. Learn more.

What are the benefits of container gardening?

• Grow organic produce anywhere — even in small spaces.
• Control soil quality, nutrients, and growing conditions.
• Easily move plants to adjust for sunlight or seasonal changes.
• Reduce weeds and some soil-borne pests.

Can you grow vegetables indoors in containers?

Yes. Choose compact crops like lettuce, spinach, herbs, or dwarf tomatoes. Provide at least 6–8 hours of light daily using grow lights. A sunny window is usually an insufficient light source for anything other than houseplants. Instead, use the correct grow lights based on the type of plant you’re growing. You’ll also need to maintain indoor-friendly temperatures.

When should I start container gardening?

Outdoors: after the last frost in your region. Find when you can grow.
Indoors: any time of year, as long as you can meet light and temperature needs. See growing requirements for popular container garden plants.

What vegetables are easiest for beginners to grow in containers?
Lettuce, radishes, green onions, cherry tomatoes, peppers, bush beans, basil, and mint.

Can you grow vegetables in a container year-round?

Yes, if you can maintain proper growing conditions. In warm climates, you can grow outside year-round. In colder regions, move containers indoors or into a greenhouse during winter and use grow lights to provide 6–8 hours of light daily.

What is the best time of year to start container gardening?

Outdoors: Start after the last frost date in your area for warm-season crops, or early spring for cool-season crops like lettuce and peas.
Indoors: You can start any time of year, provided plants get enough light and warmth.

Choosing Plants & Containers

Picking the right plants and containers is key to healthy, productive growth. Here’s how to match container size, depth, and material to your crops.

What can you grow in container gardens?

Almost anything: herbs, tomatoes, peppers, lettuce, carrots, radishes, beans, cucumbers, squash, zucchini, strawberries, potatoes, and even compact watermelons.

What vegetables grow well together in containers?

Tomatoes pair with basil, peppers, and eggplants. Lettuce grows well with radishes and carrots. Combine plants with similar water, light, and growth needs. Learn more.

How many plants can you put in one container?

It depends on plant size:

• 1 tomato plant per 5-gallon container
• 4–6 lettuce plants in a 12-inch pot
• 1 pepper plant per 3–5-gallon pot

How deep should containers be for vegetables?

• Shallow-rooted crops (lettuce, radish): 6–8 inches
• Medium-rooted crops (peppers, kale, strawberries): 8–10 inches
• Large-rooted crops (tomatoes, eggplant): 10–12 inches deep

Learn more about container depth.

What size container is best for tomatoes?

At least 10–12 inches deep and 13 inches wide, with strong support for vines via a trellis or cage.

How deep should containers be for herbs?

Most herbs have shallow roots and do well in pots 6–8 inches deep.

What’s the best material for gardening containers?

Plastic, ceramic, terra cotta, wood, or fabric grow bags. Each has pros and cons:

• Terra cotta breathes but dries quickly
• Plastic holds moisture but may overheat in the sun
• Wood insulates well but can rot without treatment
  
  

Soil, Water, and Fertilizer for Containers

Healthy plants start with the right growing medium and consistent feeding. Learn which soil mixes, watering methods, and fertilizers work best in containers.

What soil is best for container gardening?

Use high-quality potting mix, not garden soil. Add sphagnum peat moss with perlite or vermiculite for aeration and drainage. Aim for a pH between 6.0 and 7.0. Learn more.

What’s the difference between potting mix and garden soil?

Potting mix is lighter and drains well — ideal for containers. Garden soil compacts, holds excess water, and can bring in pests and weeds.

How often should you replace potting mix?

Every 12–18 months for regular containers. With the EarthBox® system, you can reuse soil for up to 8–10 growing seasons by replenishing nutrients.

How often should you fertilize container plants?

Every 2–4 weeks with a water-soluble fertilizer or use slow-release options for season-long feeding. If using the EarthBox container gardening system, you only fertilize once at the start of the season.

What is slow-release fertilizer?

A type of plant food that releases nutrients gradually, reducing the need for frequent feeding.

Care & Maintenance for Container Gardens

Keeping plants hydrated and healthy is easier with the proper techniques. These tips cover when and how to water, plus tricks to prevent drying out.

How often should you water container plants?

Check soil moisture daily. Water when the top inch feels dry. In hot weather, water once or twice a day.

What’s the best way to water garden containers?

Water the base of plants until it drains from the bottom. Avoid wetting leaves to prevent disease. If using the EarthBox, simply add water to the fill tube until water comes out the overflow drain.

What is a self-watering container?

A planter with a water reservoir that delivers moisture to roots as needed — also called a SIP (Sub-Irrigated Planter). Learn more.

Do containers need drainage holes?

Yes. Without drainage, roots can rot. Drill holes if your container doesn’t have them.

How do you keep container plants from drying out too quickly?

• Group containers together
• Add mulch or a cover to retain moisture
• Use self-watering planters
• Choose larger pots that hold more soil

How do I properly water container plants?

Water until moisture flows from the drainage holes and check the top inch for dryness.

Can I mix my potting soil?

Yes, you can create your own potting soil by combining sphagnum moss and perlite or vermiculite. This provides a light, well-draining mix.

What container materials are safe and eco-friendly?

Most standard materials are fine, though treated wood may leach chemicals. Consider eco-friendly alternatives that are food safe, such as container gardening systems from EarthBox.

Which plants work well in shaded container locations?

Choose shade-tolerant species like coleus, begonias, bleeding hearts, and ferns.

Do I need to refresh container soil every year?

Rather than full replacement, add compost or nutrients each season and replace the entire soil only every few years. EarthBox’s replant kits make it easy to refresh your container garden.

Container Gardening Troubleshooting & Common Mistakes

Even experienced gardeners run into challenges. Here’s how to prevent common container gardening mistakes and deal with pests, poor growth, and other issues.

What are the most common mistakes in container gardening?

Overwatering, underwatering, using the wrong soil, overcrowding plants, mixing crops with different needs, and poor drainage are common issues. Learn about 7 common mistakes.

What are the disadvantages of container gardening?

Frequent watering, limited root space, and ongoing fertilization are needed.

Do container gardens attract pests?

Yes, but often fewer than in-ground gardens. Common pests include aphids, spider mites, and whiteflies. Use insecticidal soap or neem oil for control. Learn more.

Can you compost in a container?

Yes. Small worm bins or compact composters work well for recycling kitchen scraps into plant nutrients. If using an EarthBox, do not use compost.

Which is better for containers: seeds or transplants?

Seeds cost less but take longer to grow. Transplants give you a head start — especially for tomatoes, peppers, and eggplants.

Why must containers have drainage holes?

To prevent waterlogged soil, root rot, and ensure excess water can escape.

What happens if I use a container that’s too small?

It can stunt growth, restrict root space, and dry out too quickly.

Maximizing Yields in Gardening Containers

Want to get more harvest from every pot? These strategies help you boost productivity without sacrificing plant health.

Does container gardening stunt plant growth?

No, as long as you choose the right container size for each crop, provide nutrient-rich soil, and water consistently, plants can thrive and produce yields equal to or greater than in-ground gardens.

Do vegetables taste different when grown in containers?

Not inherently — taste depends on plant variety, soil quality, watering, and harvesting at peak ripeness. Many gardeners find that fresh-picked container-grown vegetables taste better because they’re eaten immediately after harvest.

How much can you harvest from a container garden?

With good care, yields can match or exceed in-ground gardens — especially with high-density planting and nutrient-rich soil.

Does container gardening produce less than in-ground gardening?

Not necessarily. Proper watering, fertilizing, and using the right container size can double yields compared to traditional plots.

 

Have Other Questions?

EarthBox® has been an industry leader in container gardening for over 30 years. Our lab- and field-tested growing systems take the guesswork out of gardening — helping you develop more with less effort.

Contact us and we’ll get you the answers you need.