One of the most frequent pieces of advice we offer our customers and want to share with you is the idea of drainage for your plants. We’re focusing specifically in this video on drainage for plants in containers. The best way to explain drainage is to actually show it in action. And to start we’re going to talk about surface tension. Watch closely as the water is poured into the glass bowl. During that last pour, you’ll notice the water creates a nice bubble at the top. One more drop and that bubble would burst spilling over the sides but what’s keeping it together is called surface tension.
It’s important to know that generally your potting mix is made up of about 50% micro and macro pores. Your marco pores are the bigger spaces that drain faster with the force of gravity. Your micro pores use cohesive and adhesive forces (just like that surface tension we saw) to keep water from draining. This is where your roots will get water from.
But here’s the thing; your plant roots need air. So those macro pores need to drain. If they’re backed up with water because there’s no place for the water to drain using that gravity pull, your roots will die.
So if we have a great container there’s two ways you can create drainage for your plant. 1 is to poke holes in the bottom of the container. But if you a nice container like this glass bowl, the best way is to place rocks in the bottom. You can see instantly that when water is poured into the glass bowl with rocks, the water drains from the macro pores and sits at the bottom of the bowl in the rocks leaving room for air.
And that’s why you need drainage.