Sooner or later, most of us are going to stumble upon a container of some sort which - though the container is beautiful as the day is long - has no drainage hole. It may be a coffee mug that tells you in confidence that it has always longed to be planted with a String of Pearls. It may be a Ball jar or a paint can that simply demands to be planted with a small cactus garden. It happens to the best of us.
So, can it be done? Isn’t planting succulents into a drain-less container one of the top five ways to best kill a plant? Only if you water the plant as if it were in a pot with drainage.
Think about it this way: a succulent has a specific cycle that it needs to go through when it comes to moisture. First, the plant needs to be very dry. Then, it needs a good drink. Then, it needs to be drying again significantly in a short amount of time – 3-4 days. That’s the full cycle.
The plant itself doesn't care in the least what type of container it's planted into as long as the plant's needs are met.
So, the way to think about planting into a pot with no drainage is to think about how to provide the water cycle that the plant needs. The plant itself doesn’t care in the least what type of container it’s planted into as long as the plant’s needs are met – it needs a good drink, then it needs to dry out quickly. Rinse and repeat.
The formula that we use to achieve this at Flyleaf is to water with 10% of the volume of the pot. Before planting into your drain-less container, use a measuring cup to determine how many ounces of water the container will hold. If your container happens to be a pop-can, for example, it will hold 12 ounces of water. So, using the 10% rule, you know you’ll need to use 1.2 ounces of water once you have the can planted (and once the plant is ready for a drink).
Granted, you may not have a way to measure the 2/10’s ounce or whatever the fraction turns out to be in your situation. A standard teaspoon can be helpful since a full one holds 0.167 ounces. So, in the pop-can case, I’d give the plant the ounce of water, plus a not-quite-full teaspoon. (I wouldn’t spend too much time worrying about exactness. Getting the fraction wrong by a few points isn’t going to kill your plant. Just get as close as you can to 10%). Then, when you water, slowly pour it right on top of the root mass. This makes sure the roots are actually getting the water more than the extra soil around it (since so little water is used, you have to make it count).
Using this 10% rule meets the needs of the plant. It gets a good drink, then dries out quickly.
Two more notes:
1) I’ve been told by a few people that I’ve shared this formula with that it needed to be adjusted upward a little bit (no one has ever told me that they needed less water). After they tried the 10% rule, they found out that they needed a tiny bit more. Everyone’s homes will have different temperatures, different air-flow, different light and humidity, so 10% isn’t going to be perfect for everyone’s setting, but it is an excellent starting point.
2) It’s far easier to bring a succulent or cactus which hasn’t been given enough water back to health than it is to fix one which has had too much water. If your plant dries out too much, it’s forgiving and easy to fix. But, if it has been over-watered, trouble can happen overnight. Err on the side of too dry.
Last note: If you’d like to schedule an appointment to stop by Flyleaf between the events to learn more about plants and growing, we’re happy to help.