Size matters. In the world of horticulture, picking the wrong container is basically a death sentence for your plants, or at the very least, a recipe for a stunted, sad-looking tree that never quite reaches its potential. Most backyard gardeners start small. They buy those flimsy little starter trays or maybe a 5-gallon bucket from the local big-box store. But when you’re moving into the realm of fruit trees, large ornamental shrubs, or specimen perennials, you’ve got to think bigger. Specifically, you need to talk about 20 gallon nursery pots.
These things are huge. We’re talking about a container that generally measures around 17 to 20 inches in diameter and about 16 inches deep, though the actual volume in liquid gallons is often a bit less than the trade name suggests. That’s a quirk of the industry. A "trade gallon" isn't a true gallon, which is why a 20-gallon pot usually holds closer to 16 or 17 gallons of actual soil. If you don't know that going in, you’re going to be short on potting mix when you’re standing in your driveway with a literal mountain of dirt. It’s a mess.
The Psychology of the Root System
Plants are claustrophobic. Well, their roots are. When a tree outgrows its container, the roots start circling the interior wall. This is called being "root-bound," and it's a silent killer. Once those roots start that spiral, they often keep doing it even after you plant them in the ground. They eventually choke themselves out. Using 20 gallon nursery pots gives the root architecture enough "runway" to develop a robust, lateral system before the final transplant.
Think of it as an intermediate stage. You aren't just holding the plant; you're prepping it for the real world. A 20-gallon size is often the "sweet spot" for nurseries. It’s the largest size a single, relatively fit human can move with a heavy-duty dolly without needing a forklift. Once you step up to 30 or 45 gallons, you’re in heavy machinery territory.
Why Plastic vs. Fabric Changes Everything
You have two main choices here: the classic injection-molded plastic or the modern aeration fabric bags.
Honestly, the plastic ones are better if you're planning on keeping the plant in the pot for more than a year. They retain moisture better. If you live in a place like Arizona or Central Texas, fabric pots will dry out so fast your head will spin. You'll be watering twice a day just to keep a Japanese Maple from crisping up. Plastic 20 gallon nursery pots are also easier to clean and sanitize. You can scrub them with a mild bleach solution to kill off pathogens like Phytophthora or Pythium before reusing them.
💡 You might also like: Why Every Mom and Daughter Photo You Take Actually Matters
On the flip side, fabric pots—often called "Grow Bags"—are amazing for preventing that root circling I mentioned. The air reaches the roots through the fabric, "pruning" them naturally. The root tip dies back, and the plant sends out a bunch of tiny feeder roots instead. It creates a much denser, healthier root ball. But they look kinda ugly after a season. They get salt buildup and algae on the outside. It’s a trade-off.
What Actually Fits in a 20 Gallon Pot?
Don't put a tomato in here. It’s a waste of soil.
You want to use these for things that stay put for a while.
- Blueberry bushes: Most highbush varieties need acidic soil. It’s way easier to control the pH in a 20-gallon pot than in the ground.
- Citrus trees: Lemons and limes love the drainage these provide.
- Figs: Fig trees are aggressive. If you put them in the ground, they’ll take over. A 20-gallon container keeps them manageable while still giving you a massive harvest.
- Japanese Maples: Specifically the Acer palmatum varieties that grow slowly.
I’ve seen people try to grow pumpkins in these. It works, sure, but you have to be obsessive about feeding. Because the volume is limited, the plant eats through the nutrients in the potting mix fast. You aren't just a gardener at that point; you're a life-support technician.
The Soil Math That Breaks Your Back
Let's do some quick math, because this is where people get caught off guard. A standard bag of potting soil is usually 1.5 or 2 cubic feet. A 20 gallon nursery pot (trade size) requires roughly 2.2 to 2.5 cubic feet of media once you account for settling.
📖 Related: Sport watch water resist explained: why 50 meters doesn't mean you can dive
If you have ten of these pots, you’re looking at 25 cubic feet of soil. That’s a lot of bags. It’s heavy. It’s expensive. You should probably look into buying a "bulk yard" of soil from a local landscape supply instead of buying individual bags at the store. It'll save you 50% on the cost, easily.
And don't just use "garden soil." That stuff is too heavy. It’ll compact like concrete in a container this size, and your roots will suffocate. You need a mix with perlite or vermiculite for aeration. Throw in some pine bark fines if you can find them. It keeps the mix "fluffy" for years.
Drainage is Not Optional
Most high-quality 20 gallon nursery pots come with pre-drilled holes. But some of the cheaper ones don't, or they have those "knock-out" plugs. Check them. If you don't have enough drainage, the bottom three inches of your pot will become a swamp. Anaerobic bacteria will move in. It’ll smell like rotten eggs. Your tree will die.
I usually tell people to put a layer of landscape fabric over the holes before adding soil. It keeps the dirt from washing out every time you water, but still lets the water escape. Don't use rocks in the bottom. That's an old wives' tale. It actually raises the "perched water table," making it harder for the pot to drain, not easier. Science!
Dealing with the Weight
Once you fill a 20-gallon pot with wet soil and a tree, it's going to weigh 150 to 200 pounds. You aren't moving that by hand.
👉 See also: Pink White Nail Studio Secrets and Why Your Manicure Isn't Lasting
- Buy a nursery cart. Not a wheelbarrow, a flat-bed cart with four wheels.
- Position the pot where you want it before you fill it.
- If it’s on a patio, put it on a rolling caddy. Just make sure the caddy is rated for 250 pounds. Most of the cheap plastic ones will snap like a twig under a 20-gallon load.
Professional Tips for Long-Term Health
If you're keeping a tree in a 20 gallon nursery pot for more than three years, you have to perform "root surgery." Every few seasons, you’ll need to pull the tree out, shave off an inch or two of the root ball around the edges, and put it back with fresh soil. It sounds terrifying. It’s actually great for the plant. It stimulates new growth and prevents the plant from becoming completely stagnant.
Also, mulch the top. People forget this. The sun hits the side of a black plastic pot and cooks the roots. A thick layer of wood chips on top helps keep the temperature stable and reduces evaporation.
Where to Buy Them Without Getting Ripped Off
Don't buy these individually at a retail nursery if you can help it. They'll charge you $20 or $30 a pop. Look for "Growers Supplies" or greenhouse wholesalers. If you buy a pack of five or ten, the price usually drops significantly. Sometimes, you can even find them for free. Check with local landscaping companies after they've finished a big job. They often have stacks of empty 20 gallon nursery pots they’re just going to throw in a dumpster. It's a gold mine for a patient gardener.
Actionable Steps for Success
- Verify the true volume: Measure your pot's height and diameter. Use an online "soil volume calculator" to figure out exactly how many cubic feet of mix you need so you don't run out mid-planting.
- Drill extra holes: If you see only four small holes at the bottom, grab a 1/2-inch drill bit and add a few more around the side, near the base. Airflow is your friend.
- Elevate: Don't set the pot directly on dirt or grass. It'll sink and the drainage holes will get plugged. Set it on a couple of bricks or "pot toes" to keep it off the ground.
- Automate watering: A 20-gallon pot is too big to water with a watering can effectively. You'll get tired of it. Run a simple 1/4-inch drip line with two emitters per pot. Your trees will thank you with much faster growth.
- Feed regularly: Use a slow-release granular fertilizer twice a year. Because you’re flushing so much water through the pot, nutrients leach out quickly.
The jump from small gardening to "big pot" gardening is a legitimate milestone. It changes what you can grow and how long your plants can thrive before they need to hit the ground. A 20 gallon nursery pot is a heavy, dirty, awkward piece of equipment, but it’s the most versatile tool for anyone serious about growing trees or large shrubs in a controlled environment.