Optimal plant growth in a planter without drainage holes

Posted on September 12, 2019

Large square planter with flowers

Image by AShearer Photography at the Southcentre Mall in Calgary, AB. Planter from Modern Elite Aluminum Planter line.

You have combed through numerous online galleries and visited your local nursery, pouring hours into choosing the perfect plants for your beautifully designed PureModern planters. With this dedication, you have all of the essentials that you need to create a stunning piece of living art, and now it is time to plant. Your PureModern planter is made for enduring the test of time and elements, and you want your plantings to do the same.

The type of soil and fillers you put into your container matters almost as much as the plants themselves. With a  little pre-planning, the greenery you plant in your planters without drainage holes can thrive for years to come. 

While we know that it is important for plants to receive a steady water source, too much water creates an environment for stagnant water, root rot, and disease. It is imperative that your containers have adequate drainage. For plants to thrive, there must be a way for excess water to pull away from the root zone and promote healthy air circulation among the root tips. Depending on your container needs, there are several ways to accomplish this when there are no drainage holes. Let’s look at a few.  


Drainage for planters

Example of PureModern EZ filter bags and Ollie Plant Sipper Irrigation System

Plant Risers

Plant risers such as the Lift and Level Kit placed at the base of the containers without drainage holes are an excellent way to promote good air circulation and ward off potential disease. Elevating your pot will also prevent condensation that is developed at the base of the pot from ruining the surface it is resting on.


Fillers other than soil

Fillers are a great solution for planters without drainage holes because they allow a place for any excess water to go and have the added economical benefit of taking up space that would otherwise need to be filled with excess soil – an expensive and heavy alternative. 

When choosing a filler, there are a few important items to consider. The first is weight. Will this container remain stationary or do you plan on moving it throughout the seasons? Both soil and fillers can quickly add too much weight to the container. This is not an issue if the container will remain fixed in its place, but if you are a person who likes flexibility or re-arranging on a regular basis, you will want to take the weight of your filler choice into consideration. 

Ideal fillers are items that will not break down easily or react with soil. Some great lightweight examples of these are ping pong balls, empty plastic water bottles, styrofoam or packing peanuts (make sure that they are not the biodegradable, cornstarch peanuts). 

PureModern offers EZ Fill-ter Bags as a viable, lightweight option for filling space. While it is possible to use environmental fillers such as pine cones or sticks/twigs, please be aware that these options, while organic in nature, can carry with them additional microbes/disease as well as alter the acidic content of the soil. Better choices include sphagnum moss, coconut fibers (which have antimicrobial properties) or gritty sand. 


Ways to prevent excess water from killing plants 

You may have heard that gravel or broken pieces of pottery are a great way to promote adequate draining. Along similar lines, many garden centers will sell clay pebbles to place at the bottom of a container for proper drainage. While these items can certainly work as a usable filler, if misused they actually may impede the health of your plants if you are relying on them for proper drainage in a hole-less pot. 

Although water follows gravity downward, potting soil is water-loving and will act like a sponge, holding on to the water for as long as it can. The water will resist crossing from a finer substance (the soil) to a coarser substance (gravel or pottery shards) until it is completely saturated, leaving the dampest place at the base of the soil, and too much water at the root of the plants can lead to root rot and disease. 

Choosing a filler that easily allows water to pass from soil that is oversaturated to a filler lowers the chance of root rot and disease. Additionally, once the water has passed through the soil into the gravel, there is not a sufficient way for the water to wick back up to the roots high above

This does not mean that these coarser material choices cannot be used successfully as filler – but what it does mean is that you want to make sure that if there is not a drainage hole, there is enough space for the excess water to get well away from the soil and roots in the event the plant is overwatered. 

Placing some activated charcoal at the base of the pot is another way to discourage unhealthy stagnation and ward off unpleasant smells/disease. Or consider a water controlling dispersion system such as the Ollie Plant Sipper System. This unit is great because it controls and distributes water directly to the plant's roots as it needs via capillary action, allowing the plant to receive the precise amount of water it needs without waterlogging the root system. 


How much soil to use

Determine how much soil your chosen plants will need and choose a good quality, organic soil that will provide nutrition to your plants for months to come. On average, most plants will need 12 inches of soil to thrive, but for the best results look up your specific plants to learn how long their roots grow. Remember, because of gravity, the wettest part of the soil will be towards the bottom of the pot – by using filler you can elevate the water table to where the roots will best be able to reach the water. (For large containers, a typical ratio of filler to soil is ¼- ⅓ of the pot filler, the remaining space soil).


large rectangle planters

Image from Glass and Vine Restaurant in Miami, FL. 

Filling the Planter

After you have placed the filler, adding a layer of landscape fabric will help keep the soil and the filler separated. If you have decided to use a plant sipper this would be the time to add it ensuring that it is about seven inches from the root system of the desired plants. 

Then, add soil. As you add the soil, tamp down to fill in any extra space. Once you have a solid six-inch layer of soil, wet thoroughly and mix with your hand or a potting trowel to spread the water evenly. Add an additional six inches of soil, wet and repeat process until the container is filled. This will help ensure even and consistent delivery of water once the plants are potted. 

Finally, add your plants. Be sure to leave an inch or so between the soil and the top of the container to allow space for watering and air circulation at the base of the plant.

Just a little extra time spent prepping and planning your container ensures an artful piece of beauty to enjoy for many days to come! 

Our customers are innovative, with good taste and thoughtful design. Do you have a gorgeous planter that you feel proud of? We would love to see photos of them. Tag us at @puremodern_solutions and let the inspiring begin!

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