The Science Behind the EarthBox® Gardening System

Science Behind the EarthBox

The EarthBox® gardening system is a unique, sub-irrigated planter that allows the average home gardener—anyone from 4 years old to 94 years old—to grow a multitude of vegetables, herbs, and fruit without having a traditional, in-ground garden. It’s no secret that growing in the EarthBox® leads to a bountiful harvest; but have you ever wondered just what exactly makes the system work so well?

All About Gardening Basics: What’s in the EarthBox® Gardening System

It starts with four main components—the EarthBox® container, aeration screen, water fill tube, and mulch cover—proudly made in the USA from food-safe plastic; which is UV-stabilized to prevent fading and wear-and-tear, even with long-term sun exposure.

EarthBox® Container

The container itself comes in a variety of colors and is UV-stabilized, EarthBox Original containerBPA-free (#5 plastic); and boasts integrated caster sockets, a wide-mouth overflow drain, angled fill tube support, aeration screen supports, 3-gallon water reservoir, and two wicking chambers—these features set the foundation for a properly-working growing system

Aeration Screen

The aeration screen is the divider between the water reservoir and the EarthBox Original Aeration screengrowing media. Aligning with the wicking chambers, the screen rests in the supports around the inside perimeter of the container, and provides an air space between the water and underside of the screen. Small holes in the screen allow the roots of plants to obtain oxygen, which helps prevent root rot.

Water Fill Tube EarthBox Original water fill tube

Plants are always watered through the water fill tube, which leads directly into the reservoir. The integrated overflow drain in the container prevents over-watering. Once the reservoir is full, any excess water will flow out. The two wicking chambers in the corners of the container are packed with growing media and meet the water reservoir to promote natural wicking. Wicking occurs and the roots draw water from below to nourish the plants.

Mulch Cover EarthBox black and white reversible mulch covers

The mulch cover is a black and white reversible cover made from durable agricultural film. It is one of the most important elements of the EarthBox® gardening system that serves several critical functions to control and protect the system’s environment:

  • Keeps rain out of the growing media to prevent crucial nutrients from being washed away.
  • Prevents evaporation and conserves water.
  • Stops weeds from transplanting in the system; which would otherwise compete for space, water, and nutrients against your plants.
  • Helps deter insects and other pests from burrowing or digging in the growing media.
  • Depending on the climate and which color is face up, the mulch cover helps to attract or reflect sunlight. This assists in controlling the temperature of the growing media. Use the white side up in hot, dry climates to prevent young seedlings from dying; or in contrast, help warm the soil to stimulate growth by using the black side up in cooler climates.

Two mulch covers are included with each EarthBox® gardening system and Replant Kit: one to grow, one for snow. Properly winterizing your system at the end of the growing season will make it easier to replant in the Spring.

The Perfect Growing Recipe: Required Nutrients to Grow Healthy Plants

Just like people, plants need proper nutrition to grow big and healthy. The ideal blend of nutrients for plants to grow consists of three essential ingredients: growing media, dolomite, and fertilizer.

Growing Media EarthBox Organic Potting Mix

Plants require a healthy substrate to grow in, with just the right pH level. While the EarthBox® gardening system employs a similar technique to farming, traditional topsoil just won’t cut it in the system. By purchasing and using a sterile commercial growing medium, you are guaranteeing a safe environment for your plants to grow in, free from soil-borne diseases and pests. A Sphagnum Peat-based potting medium is recommended since peat acts as a sponge, absorbing water to deliver to thirsty plants. Commercial mixes typically have vermiculite (shiny flake mineral) and/or perlite (small white mineral) mixed in to allow for proper aeration and drainage so the mix does not become overly saturated. The right type of substrate for growing vegetables in containers does not contain rock, clay, sand, or topsoil.

Dolomite Dolomite

Dolomite is limestone that is mined from the earth. This mineral is comprised of calcium and magnesium—and, when added to your growing medium—helps raise the pH level of naturally acidic peat. Calcium and magnesium are both required elements for growing healthy fruit, and help prevent the development of Blossom End Rot (BER) on the fruit of tomato and pepper plants.

Fertilizer 7-7-7 or 8-3-5 fertilizer

Fertilizer is food that helps the plant grow. Commercial fertilizers in the United States are required to be tested and provide a guaranteed analysis. The analysis lets the gardener know the N-P-K concentration; which stands for nitrogen, phosphorus, and potassium.

  • Nitrogen: Responsible for the growth of foliage. Using a high-nitrogen fertilizer will result in a lot of green growth; which is great for growing lettuces, herbs, field greens, etc.
  • Phosphorus: Responsible for flowers and fruit development, as well as root growth. Using a high-phosphorus fertilizer will help the plant develop strong roots, develop flowers, and set fruit; which is excellent for growing tomatoes, peppers, eggplant, etc.
  • Potassium: Responsible for the general health of the plant. Using a high-potassium fertilizer will help the plant’s overall functions.

Using a dry, granular fertilizer with N-P-K between 5-15 is ideal for use in the EarthBox® gardening system. Some commercial growing media already contain fertilizer, but—due to the low concentration—additional plant food should be added during planting per the EarthBox® instructions.

Let's Get Growing!

Once all these elements are put together in the system, the plants are able to take water and nutrients—which help them grow and produce. While the EarthBox® gardening system can grow many varieties of plants, we recommend only growing one type of plant per EarthBox® system, and sticking to the EarthBox® Plant Placement Chart. Due to the nutritional requirements and maturation size of different plant types, adding too many plants will result in a decreased yield, due to competition for resources. Less is more.

Thirsty plants receive water as it moves up through the dry growing media by the principle of capillary action. Capillary action involves two important properties of water—adhesion and cohesion. Adhesion is the force that holds individual molecules of water together, and cohesion is the force that makes water molecules stick to other surfaces. Water begins adhering to small particles of the growing media and slowly works into small spaces between the growing media particles. As water adheres to the particles, cohesion allows for continuous drawing of water from the reservoir. Eventually, all the growing media becomes moistened and the plants can use as much water as they need. As the plant absorbs the water, more is pulled from the reservoir as transpiration takes place. Keeping the reservoir full ensures the plant will always have the right amount of water; never too little, or too much.

Fertilizer and dolomite provide plants with nutrients that are necessary for plant health and function. Just as water is drawn up, nutrients are pulled down. Water and fertilizer molecules diffuse or move from areas of high concentration to areas of low concentration. The fertilizer is concentrated, so it is good for the entire growing season, providing adequate nutrition to the plants.

Accessorizing Your Garden

Depending on your needs and your plants’ needs, your growing system may require additional accessories for support or watering. Different accessory items, such as casters, Garden Stands, Staking Systems, and the Automatic Watering System (AWS) make the growing experience more maintenance-free.

Caster Kit

Casters are optional, but are recommended for gardeners wishing to extend their growing season by bringing the system in and out of their home or garage during cooler nights; or for anyone with a shaded yard who may wish to “chase the sun.” The EarthBox® Caster Kit provides a set of four casters, two of which have a built-in lock to help secure your garden in place. The casters may be placed directly in the sockets on the bottom of the system, in the legs of the EarthBox® Garden Stand, or in the outrigger feet of the EarthBox® Staking System (two additional non-locking casters are provided with this product).

Staking System

Help your garden reach new heights with the EarthBox® Staking System. This provides a supportive trellis for tall and vining crops such as tomatoes, cucumbers, melons, winter squash and more. By allowing plants to grow vertically—not only are you saving space—plants can get more airflow and stay off the ground away from pests. Casters can be used on this item, so mobility is maintained

Garden Stand

Recommended for elderly gardeners, or those with chronic back pain, the EarthBox® Garden Stand elevates your gardening system to a comfortable height. Low-growing crops, such as lettuces and herbs, can also be raised off the ground away from hungry critters with the Garden Stand. Casters can be used on this item, so mobility is maintained.

Automatic Watering System (AWS)

Thirsty plants, such as tomatoes, require a lot of water when growing. It is not uncommon for two mature tomato plants to drink 6-10 gallons of water per day! The EarthBox® Automatic Watering System (AWS) delivers a constant supply of water to your plants without wasting a drop of water. A sensor placed in the water fill tube regulates the amount of water in the reservoir so you don’t have to.

Simply put: the technology of the EarthBox® gardening system allows plants to take water and nutrients when they are needed—with minimal maintenance by the gardener. By providing the plants with everything they need up front, and protecting their growing environment; they can grow rapidly and healthy—resulting in larger plants and increased crop yield.

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