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Tabbed RootMaker System


RootMaker® and the Whitcomb System®

RootMakers® are designed to create fibrous, non-circling root systems horizontally and vertically at all phases of production to equip plants for transplanting success. Our products aren't just "containers" but rather root production tools. Each step complements the next, building upon the previous fibrous root system. A fibrous root system means a greater root tip surface area and translates to a greater efficiency in the absorption of water and nutrients; an increase in growth rate, establishment, and vigor; a higher transplant survivability; and ultimately, superior performance for your customers.

start strong

Start Strong

Air-root-pruning stimulates root branching without toxic chemicals. Pictured on the left is a root without the benefit of air-root-pruning. On the right, a root that has been air-root-pruned in the RootMaker®II container. This critical air-root-pruning accelerates growth and increases efficiency. Continue the root branching with each complementary step of the Whitcomb System®. See the Steps

Finish Strong

This 6-inch caliper bur oak was grown with the Whitcomb System® and is 6 years old from seed germination. Notice root branching in all directions. After 3 months in the RootMaker® propagation container, and 2.5 years of constriction-pruning in the knit fabric container, this oak was transplanted and grown for 3 years with the fabric removed. The only mechanical root cutting was by a 52" tree spade at harvest. 


How The Original Root-Pruning Container System® works.

Before beginning nursery production, consider your seed source and its adaptability to your geographic region. For example, redbud seed from a parent tree along the Gulf Coast will produce seedlings that will be injured or killed in Tennessee or Kentucky. Conversely, redbud seed from Tennessee will produce seedlings that will grow along the Gulf Coast but may flower poorly.

RootMaker Propagation Containers

RootMaker® Propagation Containers

The first step toward creating a fibrous root system is RootMaker® propagation containers. Besides the original injection-molded 4-pack (Patent #4,753,037), there are the thermoformed RootMaker® II 18-, 32-, and 60-cell trays (USA Patent # 5,557,886). The 18 and 32-cell are also available as pull apart trays.

Choose a support flat with open mesh sides and bottom. Six 4-pack RootMakers® fit a 12" X 18" flat (Ex: Sunnyside flats from Dillen Industries). The 60-, 32-, and 18-cell RootMakers® fit a standard 10" X 20" mesh bottom/ open-sided flat.

RootMaker® Express™

RootMaker® Express™

The RootMaker® Express 18 (25 cu. in.) is an injection-molded new and improved single. Our new Shuttle tray neatly holds 18 of the Express 18's or the 18-cell pull apart singles for sorting, grafting, and grading. RootMakers® require a wire bench or other support 18 to 24" above the floor to allow good air circulation and thus efficient air-root-pruning on all sides of the container, not just the bottom.

Increases Efficiency

Increases Efficiency

These southern red oak seedlings are 3 days old. Pictured on the left is a root without the benefit of air-root-pruning. On the right,a root that has been air-root-pruned in RootMaker® II container. This critical air-root-pruning accelerates growth and increases efficiency. Continue to build this fibrous root system through all phases of production.

ingredients for success

Ingredients for Success

RootMaker® propagation containers can be filled with a mix of peat and perlite 40/60 or peat, perlite, and vermiculite 40/40/20, or pine bark, peat, and perlite at 50/30/20 by volume. Add 1.0 pound of Micromax® micronutrients, 3 pounds of dolomite, and 6 pounds of Osmocote® 18-6-12 (no substitutes) per cubic yard of mix.

Additional Branching

Additional Branching

RootMakers® are designed to direct roots into openings in the container. The first root to reach an opening is usually the tap root. Once the tap root reaches a bottom opening, the tip dehydrates and stops growing. When this occurs, secondary roots form that are more horizontal in growth habit. These secondary roots soon reach side openings, dehydrate the root tips, and create additional branching.



RootBuilder® II technology is now available in a quart sized kit. Called simply, the RBQ™, this highly efficient air-root pruning container creates a strong liner for grafting.



Timing is also very important. Once a fibrous root system has been created, it is time for the next step to a larger container. If plants are left in RootMakers® too long the benefits will begin to decrease and water management may become more difficult, due to the unique, high concentration of roots. Monitor your plants' progress. The length of time in RootMaker® propagation containers varies greatly but is typically no more than 2 to 4 months.


Seize every opportunity to continue root branching momentum.

Depending on your production requirements, there are several options. A good rule of thumb is "the 4-inch Rule". Similar to pruning shrubs, research has shown that when a root is pruned, root branching occurs at the tip to about four inches back. This is why RootMaker® propagation containers are 4 inches deep. If plants are shifted to a larger RootMaker® container with a sidewall difference less than 4 inches, excellent branching will occur but this fibrous root system will soon exhaust container volume and may require an additional shift. If plants are shifted to a container that has a sidewall difference greater than 4 inches, some root branching opportunities or sales could be missed.

The 4-Inch Rule

To illustrate the 4-inch Rule, this large rootball of a 3.5 inch diameter lacebark elm which had been growing in an 18" diameter RootBuilder® for 1.5 years, was cut in half with a chain saw. White lines indicate this tree's first year root systems from RootMaker® 4-pack and RootMaker® 3-gallon. Note the complementary effect of each container size with the next to create an extremely fibrous root system.

One, Two, Three and Five gallon liners

One, Three and Five

RootMaker® 1, 2, 3, and 5 Gallon (Patent#4,753,037) Many nurseries shift to 1, 2, 3, or 5 gallon RootMakers®, generally in May, June, or early July, then allow these seedlings to grow in this container until fall planting in the field or the next shift. All models of our 1, 2, 3, and 5-gallon RootMakers® have many openings designed to continue the air-root pruning process.

a good mix

A Good Mix

For above-ground RootMakers® , a good mix begins with ground pine bark, peat, and sand 60/20/20 by volume. To this, add 1.5 pounds of Micromax® micronutrients and 14 pounds of 17-7-12 Osmocote® per cubic yard. The quantity of dolomite required for best growth depends on the minerals dissolved in your irrigation water. Other recommendations are site specific.

In This Container

In This Container

Roots are insulated from temperature extremes and are directed to openings 3/32 inch in diameter. Through these holes, roots extend into the soil to absorb water and nutrients and provide stability. Roots cannot expand beyond the 3/32 of an inch which causes an accumulation of sugars and starches inside the container. Root branching occurs behind this constriction. At harvest, small roots outside the container are broken off. Once the Grounder™is harvested, shift the plant into any larger RootMaker®, or a cheap blow-molded pot to go to market, then reinstall the Grounder™ while the hole is still open.

RootBuilder®II HIGH 5® and RB3™

RootBuilder®II is assembled around a root-directing bottom disk to form 3, 5 (mix down several inches) or 7-gallon (completely filled) containers. This innovation greatly assists handling and creates an unparalleled fibrous root system.

Cinder Blocks

One of our most popular methods of liner production utilizes concrete cinder block cavities. Our 5" bags slip snugly into each cavity. Here, blow-over is eliminated and roots are insulated from temperature extremes, and continue the root branching procedure either by root-tip-trapping or root constriction.

Knit Fabric

Knit Fabric In-Ground

Installation of Knit Fabric containers is accomplished with an auger of same or larger size. A depth control gauge on the auger allows for a uniform 12 inch depth. It is important to level the hole bottom to prevent a "bowl" effect. The container is then set in the hole and held open with a plastic expandable sleeve. Then the container is then filled with the same field soil. At least one inch of the Knit Fabric container should remain above soil line to prevent roots escaping over the top. The system works better when care is taken to keep the sides of the fabric container straight when packing the backfilled soil.

Almost a Treat

Although somewhat labor intensive during installation, harvesting is almost a treat. For the smaller sizes (8 to 14") one person can spade around the outside of the container to sever the small roots, rock the tree back and forth, and lift the tree out of the ground. For larger container sizes (18", 24"), "popping out" with the forks of a front end loader or skid steer works well. Trees also can be harvested with a double-loop of a nylon strap, when plants are dormant and field conditions are moist.

An Accumulation of Energy

An Accumulation of Energy

With the Knit Fabric container, small roots extend through the fabric but are unable to expand, causing a constriction which leads to root branching and an accumulation of energy. Water management is less complicated in the field and the root system is protected from temperature extremes. When a tree in the Knit Fabric container, generally sizes 8" to 24" (30", 36", 48" special order) is harvested, the fabric is removed and, once planted, is provided the benefit of having a great majority of the root system not only intact, but well branched and equipped to establish into the surrounding soil horizontally rather than just downward.


The RootTrapper® Soft-sided Container

The RootTrapper® provides the mobility of remaining above ground and is generally 5 to 30-gallons at this shift. This is a black, spun-bonded fabric which has been laminated with a white coating. This unique container stops circling roots and continues to stimulate root branching by trapping root tips.

Marvel at the Root System

Marvel at the Root System

The white outer coating greatly reduces container temperature so roots do not die on the sunny side as with black plastic containers. Water usage is also reduced as there are no large drain holes or evaporative sides; water seeps out the hundreds of holes created by the base stitching. When ready to harvest, slit down the sides with a utility knife, peel off container, and marvel at the root system. We have been able to use heavy duty staples to rejoin the side wall together and reuse RootTrappers® for another season or two, at a slightly reduced diameter. (Using Arrow stapler model P-35 with 3/8 inch staples, or Stanley Bostich 9/16" C-ring fasteners).

RootTrapper® Options

RootTrapper® Options

The success of this container has led to other versions to better suit some production needs. The RootTrapper® "Grounder™" has a base material which allows roots to grow through and peg into the soil. This not only reduces blow-over but permits the plant to reclaim water and fertilizer. The RootTrapper® II is not laminated on the bottom 2 inches of the container sidewall. By allowing better drainage near the base but not totally exposing the container sidewall to rapid evaporation, moisture and aeration for the entire soil column is improved.

RootTrapper® Pot-in-Pot Insert

RootTrapper® Pot-in-Pot Insert

Now available to custom fit your socket pot. Major root escape is no longer a problem plus a fibrous root system is created by root-tip-trapping. At harvest, roots are insulated from temperature extremes.

Big Finish

Large Containers

By now the system has been in effect for at least 2 growing seasons and we are dealing with a tree/shrub of considerable size and a well-branched root system. One option is to plant and harvest in the field conventionally. Another option is the RootTrapper® which comes in sizes up to 60 gallons for continued benefits of root-tip-trapping for another season.

The RootBuilder®II Container

The RootBuilder®II Container

The RootBuilder®II expandable plastic container is another option. This highly successful, versatile container now has been redesigned and is patent pending. It comes in a continuous roll and can be cut to create the size of container you require. (Or pre-cut for sizes 15 to 70 gallon.) With a few inches of overlap, the container is assembled by connecting with cable ties, which do not block openings for air pruning.

Allows Roots to Penetrate

Allows Roots to Penetrate

The bottom of the RootBuilder®II can be our RootBuilder® base material which allows roots to penetrate into the soil, pre-cut RootTrapper® discs, or other material that is impervious to roots such as 6 mil. poly., or a spun-bonded weedbarrier type fabric which aids movement of the container.

Best Chance for Survival

Best Chance for Survival

A hole is at the tip of each outwardly projecting funnel on the sidewall of this container. For instance, a 30-inch diameter, 18-inch sidewall RootBuilder®II container is 45 gallons and contains 1600 funnel openings. However, the sum of these openings is only 6% of the container sidewall so water loss is minimal. As a result of the sidewall configuration, a portion of sidewall is shaded, reducing temperature and evaporation. Roots are directed outward to these holes and forced to branch yet again by air-root-pruning, thus completing the Whitcomb System®. If needed, the cable ties can be cut, then an additional RootBuilder®II piece can be added to create a larger container. Ultimately, this is a superior tree with a superior root system, given the best chance for survival in any landscape situation.