Updated review 07/28/18

If you have limited space for growing plants, you’ve probably tried growing in containers or elevated planters. But have you considered growing vertically?

By stacking containers on top of each other, rather than side-by-side, you can grow a lot more in a small footprint. But stability and efficient watering can be difficult with vertical planters.

That’s where the GreenStalk Stackable Growing System comes in. The patent-pending “water core” system promises to allow you to easily water all levels of the container at once and the planter design lets you stack up to five layers of plants, supposedly without the whole thing toppling over.

We put the GreenStalk planter (and the optional Mover) to the test in the hot, dry, and windy conditions of Tucson, AZ – here’s what we found …

Assembling the GreenStalk Stackable Planter

The GreenStalk planter arrived neatly packed in one box. The parts were stacked into a compact bundle and encased in plastic with a handle on top, making it easy to remove from the box and carry to the garden. Just that little detail shows the thought that went into designing the product.

The GreenStalk planter is neatly packaged and easy to carry. The parts can be easily stacked for storage.

The instructions were clear and easy to follow, and I was able to put the planter together in just a couple of minutes. No tools are required.

About the Planter

There are only 10 parts to assemble and no tools are needed. That’s my kind of planter!

The planter is comprised of five (or three, depending on the model) trays that stack neatly on top of each other. Each tray has a watering disk (a shallow tray with holes through which water drips when the disk is full) that slips neatly onto the tube in the middle of the planting tray. The top planting tray has a large water reservoir.

The GreenStalk comes in 4 colors (stone, black, green, and wood-filled) and 2 sizes (3-tier and 5-tier).

When assembled, the GreenStalk planter measures 19 inches across and 54.25 inches tall (for the 5-tier model; the 3-tier model is 30.75 inches tall). There are 30 planting “pockets” in the 5-tier model, 18 in the 3-tier planter.

The planter is made from food-grade, durable, UV-resistant plastic that’s guaranteed to last at least 5 years without fading. After six months in the harsh Tucson sun, the plastic still looks like new; I’ll keep you posted if I notice any changes over the coming months.

[Update 07/29/18] Three years later, the planter still looks and works exactly as it did when I first got it.

I like that the plastic is also recyclable (not that I intend to dispose of it any time soon!) and available with bits of reclaimed wood incorporated into the plastic.

The GreenStalk planter is 100% made in the USA.

Be careful when you stack the planting trays. It’s not at all difficult but pay attention to how the parts fit together – you need to get each one lined up correctly before they’ll snap together.

Planting in the GreenStalk Stackable Growing System

Each tray has 6 deep planting pockets and a watering disk that fits on a tube in the middle.

Fill each tray with a good quality planting mix. I prefer organic mixes so I used a combination of Kellogg Patio Plus and Amend; both are OMRI listed and full of great organic matter and nutrients for growing vegetables. You’ll need 4 or 5 bags of potting mix to fill the 5-tier GreenStalk.

I found it easiest to fill each layer separately, place the watering disks on the tube in the center, and then stack them together.

Each planting tray has six pockets in which to place plants. The pockets are deep but they aren’t very large so you’re limited to smaller plants. But there’s plenty of soil in the tray for healthy root development so the plants are well supported (they won’t tip and fall out of the tray if properly planted).

It’s easiest to fill each layer separately and then stack them together.

The company says you can put two or three plants in each planting pocket. I suppose that works for plants like carrots (there’s enough depth to the planting pockets to grow shorter carrots, like Danvers Half Long) or smaller herbs, but I wouldn’t put three tomatoes or beans in each one.

I filled the entire GreenStalk planter with both hot and sweet peppers (using mostly organic seeds thanks to the Sustainable Seed Company). They readily established in the warm soil in the planter and grew quickly. Because of the planter design, the peppers tended to grow leaves on only one side (away from the planter) and leaned out a little, but they were healthy and set fruit readily. As peppers develop and the plants get top-heavy, I’ll tie them up to prevent them from falling over. This is easily done with a few sticks or plant stakes and some twine.

Be aware that the plant roots are fairly close to the exterior of the planting pocket so can easily be “cooked” or overheated by sun exposure in warmer climates.

Watering the GreenStalk Planter

This is what I was most curious about when I first saw the GreenStalk planter.

Just fill the top water reservoir and watch the water gurgle down the center tube to fill all of the water disks below. As each disk fills, the water seeps through the holes into the soil below, slowly moistening the soil throughout each planting tray. The top water disk fills first, then the second from the top, and so on until all the disks are full.

At over 4 feet tall, the GreenStalk stackable planter is quite tall. Consider that when deciding what to plant in the upper layers. You can see the dolly we built at the bottom – invaluable for moving the planter around.

You’ll often get a gush of water out of the bottom of the GreenStalk planter when all of the water disks are full. I wish that there was a plug for the hole in the bottom tray so that this doesn’t happen but it does let you know that it’s time to stop filling the reservoir … [Editor’s Note: The company is working on a small design tweak of the reservoir to put a line around the inside indicating how much water it should hold. And don’t try to plug the hole in the bottom tray – that will result in over-watering the lower tray(s).]

I was pleasantly surprised to find that the GreenStalk’s watering system worked exactly as advertised. One of the common problems with a vertical growing system is that it’s watered from the top so water often doesn’t make its way down to plants at the bottom of the planter. That’s not a problem with the GreenStalk planter – each level of the planter gets the same amount of water at the same time. After filling the reservoir, you can see water seeping out of the holes in each water disk. Because it’s a slow drip system, you don’t have run-off and moisture makes its way to the root zone at the bottom of the planting pockets, providing even moisture throughout the entire planter. Even here in the heat of Tucson, I only had to water from the top

A note of caution – use clean water without any debris, sand, dirt, or granular fertilizer in it. I made the mistake of using a water soluble vegetable fertilizer that I sprinkled into the water reservoir. Unfortunately, it never quite dissolved and ended up plugging the holes in the watering disks. And if you have water with a high mineral content (like we do here), note that the weep holes can clog over time.

Moving the GreenStalk Planter

The GreenStalk mover comes with 3 locking and 3 non-locking casters, plus a drain tube and plug

The GreenStalk planter is heavy when full (especially after it’s been watered) so place it where you intend to leave it. Or, if sun exposure is a concern (as it is here in Tucson), use the optional Mover so that you can rotate the planter as needed or move it into the shade.

Initially, we used a piece of plywood with four casters –it worked fine but eventually rotted and broke. That’s when I found out that GreenStalk had introduced the Mover – a molded plastic “dolly” with 6 casters (3 locking, 3 non-locking) that fits perfectly onto the bottom of the planter. There’s a short drain hose that can be inserted into the bottom if you want to direct the flow of any excess water, and a plug if you want to temporarily stop water from draining (just don’t leave the plug on for long or the bottom layer of the planted can end up over-watered).

The Mover can support up to 300lbs.

The GreenStalk Mover has been a game-changer for us (because I can now easily move the planter wherever I want – over a level surface! – without any help). However, be careful because the GreenStalk planter can easily be tipped over when you’re moving it (although it’s very stable when placed on a level, solid surface) – push or pull on the lower sections to maneuver it around and do so slowly.

The GreenStalk Mover fits perfectly onto the bottom of any section of the planter

Recommendation

After 3 years of continuous use, I can’t say enough good things about the GreenStalk planter! It’s a nice solution to a common problem – effectively and efficiently growing plants in a small space. It’s well-designed, easy to use, allows you to grow a huge number of plants in a very small area, and keeps those plants evenly watered. And with the optional Mover, it can be easily turned or moved as needed.

Where to Buy

At the time of this publication, the 3-tier model is available for $99.95, the 5-tier model for $149.95. Both are available through the manufacturer’s website and on Amazon. Shipping is a flat rate of $26.95.

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Greenstalk Mover Vertical Planters

The perfect solution for moving your GreenStalk planter

$48.97

See it on Amazon