Question
I have a question about how to water - and more specifically, ensure proper drainage of large indoor potted plants. Although I am a relative beginner when it comes to houseplants, I am very diligent about not letting my plants sit in their own drained water. My question is how to deal with this with large trees that you can't very well lift up to remove the massive water-filled dish every time.   
 I recently bought a large ficus lyrata tree and re-potted it into a self-watering pot. I'm sure you are familiar with these, but it has no hole in the bottom and no separate dish underneath, but rather a drainage basin inside the pot that catches the excess water and recycles it back into the soil, all the while keeping it separate from the roots so they're not ever sitting in the water.  
I've never used one of these pots before and I'd like to know first, is this a good choice? Will it keep the roots from rotting? And second, how do I be sure I am giving the right amount of water since I can't see how much is collecting in the bottom of the pot?
 And in regards to my other large tree, it has an old fashioned pot & dish combo but after I water it I just leave the water in the dish until it evaporates because the pot is too heavy to lift! Is this ok? What is the best way to water & drain large indoor plants?
Thank you very kindly,
Taylor Cathcart

Answer
Hi Taylor,

Your concerns are good ones. The key to watering is drying out. By that I mean that all plants need oxygen as well as water in their root zone. Soil that is constantly wet or saturated with water has no room for air (oxygen) in the tiny spaces between the soil particles. When deprived of oxygen, roots gradually begin to rot and die. So the key to effective watering is allowing the soil to dry out appropriately in between waterings.

If a plant sits in a watered-filled saucer for a day or so, it will not cause a problem as long as more water is not added before the soil has dried appropriately. If the saucer holds water for more than a few days at a time, there is a reasonable possibility that root rot may begin. In general, it is best to water large plants slowly and stop as soon as you see a small quantity of water trickle through into the saucer. That small a mount will evaporate within 24 hours and will not be a problem. Should you inadvertently fill a large saucer with excess water, a turkey baster is an easy way to remove the excess water.

Your decision to move your Ficus lyrata to a self-watering planter was not a good one. "Self-watering" makes it seem like it takes all of the thinking and decision-making out of watering and that is not the case. There are many types of self-watering or sub-irrigated planters available, but because you cannot see the reservoir in yours, it makes knowing when to water more complicated. (The better systems have a mechanism for viewing the water level in the reservoir.)

I suggest you ignore the self-watering device and do the following. Allow the top one-to-two inches of soil to feel dry to the touch before adding any water. Then, add what you judge to be enough water so that the soil reaches that same level of dryness again in about a week. If it takes more than a week, then wait until it dries appropriately and then add less water the next time. You have to experiment with and adjust the VOLUME of water you add so you can get it on a weekly water-to-dry cycle.

In general, it is best to monitor soil moisture by checking the soil from the top and then adding about a week's worth of water when it is appropriately dry. This will provide adequate moisture and oxygen for the roots.

"Appropriate" dryness depends on the size and species of the plant. Cacti and succulents should dry at least halfway down into the soil. Other plants should be watered when the surface of the soil feels dry. Most plants do best when watered after the top quarter of the soil feels dry.

I hope I have not made this too complicated, but you seem interested to know the dynamics as well as the timing of watering.

I have written detailed articles on watering, repotting and on Lyrata care that I will email for free to you (or anyone else) who emails a request to me at [email protected]. I have also written an indoor plant care book in a PDF format that I can sell you if you contact me at my email address.

Please let me know if any of this is unclear or if you have any additional questions.

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Will Creed, Interior Landscaper
Horticultural Help, NYC

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