Planting Annuals in Cardboard Boxes

Too much screen time? Too much YouTube? Yup. It’s the only explanation I have for wanting to try my hand at planting annuals in cardboard boxes.

Planting veggies and other annuals in pre-formed corrugated cardboard shipping boxes is being done on YouTube, left and right. Although I hate to be a follower, I do love to join in on a nice idea. So I had to try it out. Was this a nice idea? I’d soon see.

The Concept

On-screen, Amazon boxes in particular are mentioned as “prime” (pun intended) planters. There is talk of ensuring whichever boxes are chosen are uncoated, with no printing or tape on the inside—nothing potentially harmful that might leach out into the soil. This is important for food items. Of course, with ornamental annuals, less care is needed.

I wanted to plant two food items, plus flowering annuals. For the food, I thought of past planting I had done in hard plastic trugs. Choosing cardboard, instead, seemed a step up from that in terms of being all-natural and “clean”. So I set aside a few boxes that seemed to be the best I could find. I was ready. But what would I learn?

The Experience

Eager to test out what I had seen from others, I did the following:

• I used the cardboard container method for planting seed potatoes. In the past, I got lazy when it came to mounding up enough soil around these plants once their green growth took off. With this new method, I knew that the seed potatoes would be able to start off growing in a box filled halfway to the top with soil. Once their leafy green tops had gotten tall, I would add more soil to the box. From what I had seen on “the tube”, I realized that a lot of mounding potential (actually, filling versus mounding) would exist when the flaps of the box, first folded down on the outside and not touching the soil, were brought up and secured to create taller “box sides”. 
• For a tomato plant, I filled a box with organic potting soil and buried 1/3 of the plant’s stem. Filling the box only halfway, as I had with the potatoes, would have resulted in reduced airflow around the tomato plant… not good, as tomatoes and certain annuals, such as the marigold I wanted to place near it, need good air circulation. So, I raised my filling level to avoid this problem.
• For ornamental annuals, I began to think that this planting method made little sense. It’s recycling, or upcycling. But I prefer digging flowering annuals right into the ground. And that's what I did—no box for these.

Tips

1. First, “cardboard” in this case means corrugated cardboard. You need the strength of the corrugate, and you may even need to double-box a plant or two.
2. Second, you’ll need to poke drainage holes in your boxes, with the best placement being low and along the sides (about ½-foot up, not underneath).
3. For the early part of the growing season, you’ll want extra support around your boxes—a brace of some sort. Box sides slump and flump quickly, putting your growing annuals at risk of toppling over.
4. Use cardboard boxes in an open area, away from your home or outbuilding. Damp cardboard can attract creatures that you don't want in your home.

Thoughts on the Method

Testing out this method of planting annuals seemed important at the start of spring. So what did I learn?:

Well, to be frank, it was not for me. I used it for planting in May, and I got so tired of it, I now (in July) have transplanted my potatoes and my tomato plant directly in my garden. I will miss the opportunity to cut open my potato box in autumn and let the bounty spill out. But my double-box had slumped so much already that there would have been no drama, no impressive reveal in the fall.

I liked the fact that this method involves upcycling. But my boxes degraded much faster than I expected. Watering by hand, I could direct the flow toward the bases of the food-producing annuals, and my boxes stayed dry. But rain did my boxes no good. Despite bracing them, I had a mess on my hands very early in the season.

Although “messy” doesn’t bother me if it serves a purpose, I didn’t see the purpose of this particular mess. With unglazed terra-cotta and other plant pots being reasonably priced, and with some pre-made raised beds selling at low cost, I strongly believe that there are better options for planting annuals such as veggies. I can see the appeal of the cardboard box method’s portability, provided the boxes are small and strong enough. For example, using cardboard boxes in planting fruiting annuals such as fragaria, or ornamental strawberries, would allow for quick relocation if bunnies and other creatures began to take interest in the fruit. The boxes could be moved to higher ground. Still, this can be done with other, sturdier and more traditional containers.

I suppose that if your garden soil is poor, the boxes are fine to use. They allow for control over the small bit of soil you're planting in, and they’re not much different from the burlap or tarp-like veggie bags that some gardeners like. And I have to say that they are a step above a plastic bucket from the hardware store. But the difference—which at first was a selling point to me—is the decomposition of the container. Unfortunately, mine degraded so quickly, I lost appreciation for the method.

Summing Up

I could say, “Don’t believe everything you see on t.v.” But you can actually believe the folks who try this method and like it. I know that some must have great success with it. My notes here simply show one person’s experience. You might try this method and like it. On a different year, I might try it again and have some success with it. But for now: To the recycling bin, my cardboard will go, while my annuals thrive in traditional containers.

Don’t let what I have noted here stop you from turning off “the tube” and trying some new planting methods for annuals. Not all work out and become well-loved methods… but hey, they’ll give you something to talk about.