How Deep Should a Planter Box Be?
Planter boxes are a great way to grow vegetables and produce in a small space. You can place them on balconies, patios, or even indoors. They come in a variety of sizes and materials.
However, the biggest concern is depth. You need to ensure your planting box is deep enough to handle the root system for your plants.
Why is Depth Important for Gardening Containers?
Very simply, it determines how much room the roots of your plants will have to grow. Some types of plants, such as lettuce and herbs, have shallow roots. So, they can thrive in a gardening container that's only 6 inches deep.
Other plants like tomatoes, carrots, and potatoes require more rooting depth. They need a planting box that's at least 12 inches deep.
If you give vegetable plants too little space to grow, it cramps the roots. And that stunts their growth. It may even kill the plant. But one thing is sure -- your yields will fall well short of your goal.
Best Planting Box Depths for Different Vegetables
The good news is that you can grow various plants in indoor and outdoor planters.
Here is a general guide for how deep a planting box should be. It's also essential that your planting box has holes in the bottom for drainage.
The only exception is sub-irrigated planters (SIP) like those from EarthBox (they get great reviews). They include a reservoir at the bottom to provide a steady moisture supply to plants through capillary action.
Shallow Root Vegetables
Shallow-rooted vegetables should be at least six inches deep. They include lettuce, spinach, herbs, radishes, and green onions.
The EarthBox junior gardening container is perfect for shallow plant roots at more than seven inches.
Medium Root Vegetables
These vegetables (and fruits) include carrots, beets, broccoli, cauliflower, cabbage, peppers, and tomatoes. You'll need a planting box that's 12 inches deep.
EarthBox original planting boxes have been a staple for gardeners growing tomatoes and peppers. The company even offers a tomato-growing kit with everything you need for a big harvest.
Deep Root Vegetables
Potatoes, sweet potatoes, asparagus, melon, and squash feature deep roots. For example, potato roots extend at least 18 inches below the seed. That means you need a growing box that's at least that deep and preferably deeper.
Tips for Growing Vegetables in Gardening Containers
Now that you know how deep your planter box should be, here are other growing tips.
- Use a soil mixture that drains well and contains plenty of organic matter. Organic matter helps to improve drainage, aeration, and water retention. A good option includes a mix of potting soil, compost, and vermiculite. You can also purchase commercial planter box soils.
- Choose a sunny spot for your planting boxes. Most vegetables need at least six hours of sunlight per day.
- Water your plants regularly, especially during the hottest months.
- Fertilize your plants every few weeks with a balanced fertilizer like 7-7-7. You can use a water-soluble option and include it with your watering routine.
- Mulch your plants generously to help retain moisture and suppress weeds.
- Keep an eye out for pests and diseases. Act the minute you see any street signs.
Guarantee Your Success with EarthBox Gardening Containers
Planting boxes are a great way to grow vegetables and produce in a small space. By choosing the proper depth of the planter box and soil, you can enjoy a bountiful harvest from your container garden.
EarthBox planting boxes have been a hit with gardeners for over a quarter-century. They come with a 100% satisfaction guarantee. You can also get free shipping on orders over $149.
With EarthBox gardening containers, you can grow produce anywhere, even in the smallest spaces.
If I plant a blueberry bush in the Root and Veg Earthbox, what is the method and schedule to replenish fertilizer? What about replacing the plastic cap as it inevitably wears out? How would one do this without disturbing the plant too much or making a huge hole in the next plastic cap to fit down over the bush?
I’d love to also know the same for planting blackberry bushes in the EarthBox Original?
You'd follow our instructions for the initial set up, except do not add dolomite to the blueberry bush. When you have to replace the cover, the only way for these plants is to create a big hole in the cover and then tape it back up after you have it in place. We'd recommend adding another pound of our 7-7-7 fertilizer (or another equivalent, slow-release fertilizer) every 3-4 months. That generally lasts 1 growing season, which for the majority of crops grown in the EarthBox is no more than 120 days. Blueberries and blackberries are one of the few perennials that can be successfully grown in the EarthBox.
Which size is best for blueberries the orginal size? Or the deep root n veggie size?
Can nursery recommended acidic soil/ Azelia soil be used in earthboxes for blueberries?
You can grow blueberries in either of those EarthBox sizes, though we recommend the Root & Veg since its depth is more conducive to the plant. You can forgo using dolomite with blueberries, but ensure the pH is somewhere between 4.5-5.5. We still recommend following our growing media recommendations listed here: https://earthbox.com/learning-center/recommended-growing-media
I have my SEASCAPE Day-neutral strawberry seeds in hand. These will be planted indoors, in a grow tent, under LED quantum panels in the EarthBox. I have never planted strawberries of any kind, so Im eager to get this party started. Will provide updates. Too bad we can't attach pics.
~Kbore
NEWS FLASH from Kbore about Seascape seeds: Hybrid strawberry seeds are NOT true to the variety, if they sprout at all. I may have seascape seeds in hand (rip-off) but they will not produce the same plant as the seed donor. To grow the true variety, you must have live/ dormant plant starts from that variety.
On the subject of plant starts, it's too hot to ship live plants in the middle of July (in Zone 6A where I live), so don't expect to buy strawberry seedlings mail-order: It's not going to happen.
Looks like mid-September-ish for me. As the late Tom Petty wrote: " Waiting is the hardest part".
~Kbore