You just learned about the benefits of growing your own organic vegetables.
And someone suggested using a planter box. But you are not really sure if that would work.
You can grow vegetables in a planter box that has the required size. You choose the planter box based on the leafy vegetables, root vegetables, fruiting vegetables, or herbs that you grow. Ensure the planter box uses non-toxic construction material and paint.
In this post, I’ll help you understand the benefits of growing vegetables in a planter box. And all the steps you need to grow your favorite vegetables.
What are the advantages of growing in a planter box?
Grow plants in a controlled environment
You don’t need to rely on your garden for having good soil. You can use good potting soil in the planter box.
You can make sure the planter box is in a suitable position to get the required sunlight or shade as required.
If it gets too cold, you could move the planter box indoors to your garage or basement that is warmer.
Easy to move plants around
You can have small planter boxes that are easy to move around. Or you could place the bigger ones on a dolly with wheels.
This helps move the planter boxes to a location you would prefer. If there is a lack of sunlight in one location, you can move it to another.
If the outdoor weather gets too cold, you could even more the planter box indoors in your garage or basement.
You could move the planter boxes even if you wish to rearrange your garden and improve the aesthetics.
Restricted growth of invasive plants
There are some plants that are invasive and will overpower the other plants in your garden. These plants compete for nutrients with other plants.
The benefit of using a planter box is to restrict these plants in their own space so they won’t be able to interfere with the other plants.
Less physical effort required
You can have the planter box raised above the ground, so it’s easy to work with the plants and soil. You don’t have to bend as much as you would with an in-ground garden.
It’s also easy to access the plants and potting soil because of the small size of the planter box.
Plants growing in the planter box have fewer chances of weeds growing because of the controlled environment. So you don’t need to spend as much effort removing weeds.
Grow plants even in limited space
Many people stay away from gardening because they don’t have the outdoor growing space for a large garden.
But a planter box can help you grow vegetables even in a limited growing space. You can use small planter boxes outdoors, on your patio, driveway, or even your apartment balcony.
Less chance of weeds, pests, diseases
The planter box helps grow plants in a controlled environment. It will keep the plants away from the pests, diseases, and weeds carried over from the garden soil.
This does not mean your plants won’t face these problems, but it will be significantly less.
Fewer gardening tools required
You need fewer tools when working on plants in a planter box. You would need basic stuff such as gloves, a trowel, watering can, and pruners.
But you don’t need to spend money on costly equipment such as tillers, weeders, shovels, etc.
What are the disadvantages of growing in a planter box?
Initial cost can be high
There are certain costs you will deal with compared to regular gardening. You need to invest in good potting soil if you want to grow vegetables.
You would also need to spend money on compost and fertilizer to get the best harvest out of the vegetable plants.
There is also the cost of the planter boxes, depending on the type you buy. A wood planter box is cheaper than a metal or concrete one.
More watering efforts required
Plant roots grow deep into the ground in search of moisture. But when you grow them in a vegetable planter box, they have limited soil to get this moisture from.
This means you will need to provide frequent watering to the plants compared to growing them on the ground.
How often you would need to water would depend on the type of plant and the weather.
You could reduce the watering efforts if you use drip irrigation, but that makes sense only when you have lots of planter boxes in the garden.
Read more: 11 Pros and Cons of Container Gardening
How to grow vegetables in a planter box?
1. Choose the right planter box
The first thing to do is select a planter box that is right for your garden needs. This would depend on how much space you have, the location, your budget, etc.
If you are really tight on budget, you can consider building your own planter box using some old wood pallets. Otherwise, it’s best to buy a good quality one from a garden center or online store.
Make sure that the planter box is made from untreated wood, so it’s free from chemicals. You don’t want to risk chemicals leaching into the potting soil where you’re growing vegetables.
You pick the planter box based on the vegetables you want to grow in it. Leafy vegetables can grow in a planter box that is 6-8 inches. Root vegetables can grow in a planter box that is 8-14 inches. And fruit vegetables can grow in a planter box that is 12-16 inches.
I’ve created a list of 61 vegetables and the planter box size you would need to grow them.
2. Ensure good drainage in the planter box
A common problem beginners face when growing vegetable plants is overwatering them. This can happen if the water collects at the bottom of the planter box.
So make sure there are drainage holes at the bottom. The excess water will drain out of these holes and prevent overwatering issues.
Typically, planter boxes you purchase will come with drainage holes. So check when buying them.
If you’re reusing some old box at home or you already purchased one without drainage holes, you’ll need to drill them yourself.
3. Seal the planter box
You can seal or paint the planter box to extend its life, especially when it’s made from wood. Sealing will help protect it from moisture.
You can use a 50:50 solution of raw linseed oil and mineral oil for the sealing. The linseed oil will seal the planter wood while the mineral oil will work as a thinner so it’s easy to apply.
Apply the solution on the inside and outside of the planter box. And keep it to dry for a few days.
4. Line the planter box
Line the planter box to improve its durability even more. The benefit of using a liner is it keeps the potting soil away from the planter material.
You can use material such as plastic or landscape fabric to line the inside of the planter box. Use heavy-duty staples so the liner is firmly attached to the planter and won’t shift after adding soil.
Read more: Do I Need To Line My Planter Box?
5. Pick the right location for the planter box
It’s important that your vegetable plants get the required sunlight to grow well. Most plants would need at least 6 hours of direct sunlight.
If you want to grow fruiting vegetables like tomatoes, peppers, or cucumbers, it’s good to put the planter box in a location that gets 8 hours of sunlight.
It’s good to have the planter box in a location with access to water. You’ll need to use a watering can to water the plants. And don’t want to spend effort carrying it for a long distance.
6. Add potting soil to the planter box
Once your planter box is ready at the right location, you can add potting soil to it. The quality of potting soil is really important for growing healthy vegetables.
You can’t use garden soil in a planter box because it’s very dense compared to potting soil that is airy. The potting soil helps air and moisture reach the plant roots.
Add the potting soil in the planter box till it almost reaches the top. Keep 1 inch space empty from the top of the planter box. This prevents the soil and water from spilling over when watering the potting soil.
7. Organize the planter box
You may want to grow multiple vegetable plants in a planter box depending on the size. You need to check the spacing requirements of each vegetable seed or seedling.
You can figure out the vegetables that grow well together using the concept of companion planting. You can even borrow ideas from the concept of Square Foot Gardening for your planter box.
If you have multiple planter boxes, you can design how you will place them in your garden space. Make sure there is plenty of space between planter boxes so you can move around them with ease.
This helps you work comfortably when tending to your garden, such as watering, fertilizing, pruning, or checking your plants.
Read more: How Many Plants In A Pot?
8. Put seeds or seedlings in the planter box
You can now place the seeds or seedlings you purchased in the planter box. Check the seed packets or seedling tags for more information.
You need to plant them at the right time when the weather is suitable. And you need to plant them to the sufficient depth in the potting soil as required for each plant.
There are some vegetable plants that you put the seeds directly in the planter box. But for some other plants you need to start them in a seed-starting tray and later transplant to the planter box.
We can plant directly many leafy and root vegetables into the planter box. Many fruiting vegetables like tomatoes and peppers are better started on a seed-starting tray and moved to the planter box.
If you can’t find the information on the seed packet or tag, there are plenty of online resources and books with the information. You can find information about several popular vegetables on our website using the search box at the top.
Plant 2-3 seeds per space in the planter box. This increases the chances that at least one seed will germinate.
If more than one seed germinates, you allow them to grow a couple of inches. Then you can keep the healthy plant and cut off the other one. This is known as thinning the plant.
Give the potting soil good watering after you have planted the seeds or seedlings.
9. Watering plants in the planter box
Once the vegetable plants are planted and growing in the planter box, you need to provide water regularly.
My suggestion is to check on the potting soil every morning. Stick your finger or a chopstick 2-3 inches into the potting soil. If it comes out completely dry, you can water it. Otherwise, it’s still moist and you avoid watering.
I prefer to water the plants in the morning before the sun comes out so the excess moisture evaporates. Otherwise, it can create a humid condition on the plant and attract fungal diseases.
When you water the plants in the planter box, give a deep watering. This means you use a watering can and keep pouring water until it drains out of the drainage holes at the bottom. This ensures that the roots of the vegetable plants will grow deep, healthy, and strong.
10. Fertilize plants in the planter box
Once the vegetable seedlings have grown and a month has passed, you can start adding fertilizer to the potting soil.
I would suggest adding an organic, slow-release fertilizer every 15 days so the vegetable plants can have good growth.
When you want the foliage of the plants to grow, you can choose a nitrogen-rich fertilizer. I prefer to use organic fertilizer such as cow manure and neem cake powder.
For fruiting plants, once the flowers appear, it’s good to use a phosphorus-rich fertilizer. Because it encourages flower and fruit growth. I like to use wood ash on my fruiting plants.
Put a layer of 1-inch fertilizer on the potting soil and then use a fork or trowel to mix it into the potting soil. Give the potting soil a good watering after you have added the organic fertilizer.
11. Prune the plants in the planter box
Pruning means trimming some of the foliage every few weeks. The benefit is that pruning encourages the plant to grow more even more foliage.
I would suggest not pruning over 25% of the plant at one time. Remember to prune the parts of the plant that are dead or unhealthy, such as yellow leaves and dry branches.
You only need to do this for plants that grow tall. So you won’t need this for leafy or root vegetables.
Clean the scissors or pruners before using them. You can wipe them with a solution of rubbing alcohol. This helps protect the plants from any bacterial diseases.
12. Harvest vegetables from the planter box
The vegetables you grow will have different maturity dates depending on the type and variety of the vegetable. You’ll find that information on the seed packets or tags.
Once they reach maturity, you can harvest the vegetables. Use a clean pair of scissors or pruners to clip the fruits or leaves off the plants.
You’ll get multiple harvests of leafy vegetables, herbs, and some fruiting vegetables during the same growing season.
You can harvest leafy vegetables and herbs when they have grown about 4-6 inches tall by clipping the leaves. And they will continue growing more leaves during the growing season.
You can harvest vegetables like tomatoes, cucumbers, peppers, and eggplants multiple times during the growing season, depending on the variety and length of the season.
How to store the planter box after the growing season?
Remove all the potting soil and add it to the compost pile if you have one. The other option is to put it in a bag for the next growing season.
You’ll need to sterilize it before use if there were any pest or disease problems in the plant. Or you’ll need to improve the potting soil by adding compost and organic fertilizer.
Remove the plastic or landscape fabric that you used as a liner in the planter box. If it’s in good condition, you can fold it and store it for the next growing season.
Make a mixture containing 1 part bleach and 9 parts water. Use a toothbrush (or paintbrush for larger planters) to scrub the inside and outside of the planter box. This will help sterilize the planter box and remove any diseases.
Keep the planter box for an hour so the solution can do its work. Then you can rinse the planter box with clean water and let it dry.
Once the planter box is dry, you can store it in a dry place, such as your garage or basement.
Read More: How To Clean Wood Planter Box?
What are the best vegetables to grow in a planter box?
You should be able to grow most vegetables in a planter box with the process we discussed. Here is a list of planter box vegetables that you can consider growing as a beginner.
|Bok Choy||Cool||45 days|
|Mustard Greens||Cool||70 days|
|Swiss Chard||Cool||60 days|
|Sweet Potatoes||Warm||170 days|