Planting in Non-Drainage Containers

I have worked with potted plants both inside and outside for over 37 years. I have discovered that the material that the pot is made of has no bearing on how well a plant will grow. I have used Styrofoam, metals, plastics, wood, clay and ceramic, all with very good results. As long as the plant has the needed light, proper amount of water, air circulation and temperature, it will grow as well in all the above types of materials. The main difference is if the container has a hole in the bottom.

I have hundreds of houseplants in my home, I could not fathom life without living and growing things around me, and I use mainly ceramic and some metal to plant in. I have many plants in containers that do not have a drainage hole in the bottom. The plants that do not have a drainage hole in the bottom of their pots have a layer of drainage material, such as small pebbles, to act as a water reservoir for any excess water that the soil cannot hold after watering the plant. This is ideal for those plants that need a lot of water to keep their soils evenly moist at all times. Most ferns do not like to have their soils dry even a little, especially those with very delicate leaf structures. I have a large number of ferns throughout my home. As usual , there are exceptions to the above rule. The ferns that have large, thick leaves can have a sight dry period between waterings, especially in winter.

The reason I use these non-draining pots is because the soil stays moist longer and I do not have to water as often. The stones in the bottom of the pot create a storage area for excess water. As the top of the soil dries, capillary action moves the water up into the drier soil to keep it evenly moist. Then as all the soil dries and the plant needs watering again, I water the plant enough to refill the reservoir.

There are questions here that I know many readers may have; How will I know when to water, and how will I know how much water to give the plant. It is important to know that over watering a plant is much easier with these types of pots, but with a few simple guide lines this issues is not a problem. As the plant uses water, the soil begins to dry on the top because that is the area most exposed to the air. Both photosynthesis and evaporation use water in the soil. Once the surface becomes dry below the top 1/3 of the soil, it is time to water. Only give enough water to fill the pot to the top edge. There should always be at least 1/4 to 1/2 inch of space between the top of the soil and the top rim of the pot to allow for proper watering. Once this area is filled, and as the water drains into the soil, excess water will go into the storage area again waiting to be taken up into the soil as it dries. I have plants growing for years in these types of pots. This is a type of self-watering system. There are many types of "self watering'" pots sold that use the same principle to keep the soil moist for longer periods.

Using ceramic pots with no drainage are ideal for hanging plants over areas that should not have water dripping form above.

So how do I know when the top 1/3 of the soil is dry? I use my finger to poke into the soil to feel the moisture level. There are those water meters, the thermometer-like meters, that give the moisture level of the soil when inserted into the pot. They, however, can be misleading if not used properly. Instead of purchasing a meter, get used to using your finger to test the moisture content. It is much cheaper and usually never misplaced, nor does it break (at least not frequently)! Don't be afraid to get your finger dirty and poke it into the soil down to the first knuckle. If the tip of your finger has a bit of soil on it when you pull it out, it is time to water. If there is no soil on the tip, then you may have waited too long before watering the plant. If more of the finger is dirty, then it is not time to water yet. Wait until only the tip gets dirty.

This is one of the simplest methods of determining if a plant needs water. It is a great method to use for those plants that need the surface dry a bit before watering again. Remember, no plant (except a true cactus) should EVER have more than the top 1/3 of the soil dry between waterings. Allowing too much of the soil to dry leads to water stress. For true cacti, allow the top 1/2 to 3/4 of the soil to dry in the winter, especially in the northern states.

These types of containers are time savers for those annual planters that guzzle water daily. Pots that do not have holes in the bottom need to have a least 1 inch (for a 10" pot, more for larger planters) of drainage material on the bottom. They also must be in a protected location where rain will not fall into the container. A heavy rain fall will swamp the plants. They are ideal for covered porches with plants that need shade and a lot of water, such as impatiens and fuchsias.

To determine the watering needs of large-potted plants, use the 1/3 ratio as well. Your finger may need to go the second knuckle or even third (the entire finger) to be sure you are down far enough to make sure the soil is dried enough for the plant's needs.

If you follow these guidelines when watering, the process is less confusing and will result in happier, healthier plants.