10 Container Gardening Tips

Tomatoes being grown in an EarthBox container gardening system

Container gardening is a great way to grow your own food and herbs. That’s particularly true if you don’t have much ground to work with. But even gardening enthusiasts with plenty of available space often get a kick out of using gardening containers to grow tomatoes, peppers, cucumbers, and other fruits and vegetables. So, here are 10 container gardening tips to help you grow healthy plants with big yields.

1. Choose the Right Container

The first step to successful container gardening is choosing the correct container. The container size depends on the type of plants you want to grow. For example, tomatoes and peppers need larger containers than herbs.

You can learn more about growing tomatoes and pepper by visiting the growing tomatoes in containers and growing peppers in containers blogs.

Generally, you want to select a container that’s at least two inches larger in diameter than the pot holding the plant. You also have to pay attention to the container’s depth. Plants like carrots need adequate depth to grow. Conversely, spinach, lettuce, and onions don’t require a deep planter owing to their shallow root system.

Some container gardening companies, like EarthBox, have growing guides to show you what grows best in different gardening containers. Those guides will also help you understand the plants best suited to grow at your location.

The material of the container is also important. Some materials, such as terra cotta, can dry out quickly, while others, such as plastic, can retain too much water. Ensure the container has drainage holes to prevent water pooling at the bottom. And that brings us to our second container gardening tip.

Tomatoes, carrots, and herbs being grown in different EarthBox gardening containers

2. Make Sure Your Planting Box Has Adequate Drainage

Drainage is essential. Without proper drainage, water pools in the gardening container. That translates to waterlogged roots and root rot that will kill your plants.

Drainage is essential outdoors, where heavy rain can quickly leave your plants in a pool. However, with appropriate drainage holes, excess water can escape.

It’s best to select gardening containers with pre-drilled drainage holes or a built-in overflow drain. But if you stumble onto a planter you like without those, you can always drill or punch holes into the container. And don’t be shy about making the holes. You can’t have too much drainage.

3. Combine Plants with Similar Growing Needs

Companion planting can help improve plant health and production. So when you plant your gardening container, focus on using plants that have similar sunlight, nutrient, water, and soil needs. You’ll also want to use plants with similar growth rates and sizes.

Otherwise, you might have some plants flourish while others stagnate. For example, although all plants need nitrogen, leafy vegetables require more to help them develop their leafy greens. On the other hand, tomatoes prefer high-phosphorus fertilizer to promote seedling growth.

Besides nutrient requirements, if one plant grows faster and larger than another plant in the planting box, it can block sunlight from hitting the smaller variety and stunt its growth. For instance, squash plants grow quite large. So, if you plant peppers with them, they’ll often block sunlight from the peppers.

You can learn more about companion planting here.

Companion planting infographic for EarthBox Original container gardening system

4. Select Plants with Similar Sunlight Requirements

When choosing plants for your container garden, it's essential to consider the amount of sunlight your container will receive. Most garden vegetables prefer full sun, meaning at least six hours of daylight. However, some perform better with eight hours. Fruiting crops like tomatoes, peppers, squash, cucumbers, and beans want all the sunlight they can get.

Indeed, only some vegetables grow in shady locations. The minimum requirement is three hours of direct sun, with four to six hours preferred. Under those sunlight conditions, you can grow leafy crops like spinach, lettuce, and endive. Broccoli, peas, celery, onions, and asparagus can also tolerate partial shade conditions.

And as mentioned, be careful about planting large plants with small plants. Otherwise, the smaller plants will get less sunlight and suffer. In addition, avoid overplanting your gardening containers. Plants need room to reach their mature size.

5. Choose the Right Soil Mixture for Your Gardening Containers

Not all potting mixes are created equal. When choosing a potting mix for your container garden, look for one specifically designed for containers. That growing medium will have a good balance of drainage and nutrients.

Never, and we can’t stress this enough, never use soil taken directly from the ground in your gardening containers. It won’t provide adequate drainage. Plus, it can compact and suffocate your plants.

If you insist on using ground, mix it with other materials like perlite, vermiculite, peat moss, and compost to loosen the soil and allow for drainage and oxygenation.

Better still, some container gardening companies specifically blend soil mixtures and fertilizers for their containers. For example, EarthBox has a planting kit featuring an organic potting mix and specialized plant food. Whatever gardening container you use, follow any container-specific growing media guidelines to guarantee your gardening success.

6. Water Your Planting Boxes Regularly

This may sound obvious. But it’s imperative to pay attention to watering your plants.

Containers dry out more quickly than in-ground gardens, so watering your container plants regularly is critical. The watering frequency will depend on the type of plants you're growing, the size of the container, and the weather conditions.

Most container plants will need to be watered every day or two. In extreme heat, you may need to water plants twice a day. The rule of thumb is to water whenever the potting mix feels dry to the touch.

When you water, it’s best to do so in the morning. And focus on watering the soil, not the plant’s leaves. That’s particularly true if you water later in the day or evening. Wet leaves are susceptible to diseases when things cool down overnight.

Your other option is to go the self-watering route. For instance, EarthBox offers an automatic watering system with its planting boxes. All you have to do is set it and forget it. It provides a constant water source for your container garden.

Water being poured into the water fill tube of an EarthBox planting box

7. Fertilize Your Plants Frequently

When it comes to fertilization, you face the same concern as watering. Container plants need to be fertilized more often than in-ground plants. This is because plants consume the nutrients in the potting soil within two or three weeks.

In addition, nutrients can drain from the container. Moreover, a limited supply of nutrients is available in a gardening container.

Consider adding a slow-release fertilizer to your potting mix at the beginning of the growing season. It will help feed your plants for an extended time.

However, it’s best to supplement that with a consistent fertilizing regimen. A balanced fertilizer will have equal nitrogen, potassium, and phosphorous (NPK) parts. You may see it as 2-2-2 or 7-7-7 on the label. However, you’ll usually get the best results using a fertilizer with NPK analysis numbers between 5 and 15.

As mentioned, however, some plants need higher concentrations of one nutrient than another. For example, tomato fertilizer is typically formulated with 3-4-6 or 4-7-10 to deliver more phosphorus to the plants. Always follow the fertilizer recommendations provided by the container gardening company. The ideal fertilizer ratios can vary between gardening containers.

8. Protect Your Plants from Pests and Diseases

The good news is that container plants are less susceptible to pests and diseases than in-ground plants. That’s because potting soils aren’t exposed to them as the ground is. In addition, it’s easier to check gardening containers for issues.

If you spot pests on your plants, mitigating the issue is less of a hassle owing to scale. You have a contained space to address versus an entire bed of plants.

You can also use protective netting to stop birds and bugs from damaging your plants. The net allows air circulation and UV rays through but prevents access from unwanted pests. For larger pests like squirrels, BONIDE and others provide safe repellants to humans and animals.

9. Don't Be Afraid to Prune Your Plants

Pruning has several benefits. First, it keeps your plants from getting too large. Second, it prevents plants from getting lanky. Third, it promotes air circulation, which helps plants dry out more rapidly after watering to avoid diseases.

With some plants like eggplants and peppers, heading (cutting off flower buds) removes flowers you don’t want. In addition, it encourages branching to create fuller yields.

Pinching involves removing the plant’s growing tips. It encourages plants to grow bushier and more compact. It also helps produce more produce in less space. Vegetables like green beans, chili peppers, broccoli, cauliflower, and tomatoes benefit from pinching.

10. Have Fun with Container Gardening!

Even if you don’t have a green thumb, container gardening is a great way to add color, flavor, and life to your home. With some planning and effort, you can create a beautiful and productive container garden that will provide fresh fruits, vegetables, and herbs all year.

So our final tip for container gardening is to have fun. And get your family involved. It’s a great way to get kids interested in gardening.

Outdoor garden space with swing and EarthBox gardening containers

EarthBox Planting Boxes Make It Easy

Our sub-irrigated growing systems give you everything you need to be successful at container gardening:

  • Gardening Container
  • Aeration Screen
  • Water Fill Tube
  • Mulch Covers

You can add casters to make the planting boxes easy to move. And our growing media and fertilizers are designed specifically for container gardening.

You can select from our Original planting box system, Junior herb planter boxes, or our Root & Veg vegetable planting boxes.

Whichever you choose, you’ll get an award-winning product that’s been a top-rated container gardening system for nearly 30 years.