Also supplied as a fast growth container, a tree container or a plastic container, this is the tree root container in the sizes that landscape and nursery trees actually need. The wall is a perforated polyethylene band that the root system is grown against on purpose, and the unit is built to be lifted, moved and set out again on a project rather than to sit still on a bench.

The container is quoted from 20 cm up to 2 m in diameter, and that range is why it is used for trees and shrubs being grown on to a plantable or saleable size rather than for bedding plants. The same three-part construction runs right through the range: a bottom that carries the load and controls the main root from twisting, a concave-convex surrounding whose small holes provide the side-roots air shear, and a fastening that closes the wall, holds it solid and is easy to use. At the large end this is a working container for a compound or a field block.

What the wall does for the plant is the same as at small sizes. A root tip that reaches one of the holes meets air instead of moist substrate, stops extending, and the plant pushes out side-roots further back; the side-root of the seedling increases through this physical effect in shaping, and the bottom separately keeps the main root from coiling. The result at the end of the cycle is a branched root system spread through the volume of the container rather than a single root wound around the base, which is what the range describes as a remarkable increase in roots. Where a project starts its own stock, the seedlings are normally raised first in a rooting-cuttings tray and then moved into trays for hardening off before planting out.

Two measurements taken off the tree drive the choice, and neither of them is the pot size the tree came in. The first is the trunk caliper measured above the root collar, read together with the height of the tree: those two figures set the root ball that has to come out of the container in one piece, and the container diameter has to be chosen clear of that root ball. The second is the canopy spread the tree is expected to carry when it is lifted or sold, because that dimension is what the block has to be laid out for.

The height is chosen separately, from the depth of the root ball and from the way the container will stand - on hard standing, on a nursery bed, or on the ground at a project site. Diameter and height are therefore always quoted as a pair: 20 cm to 2 m across, 20 cm to 80 cm high, and the container can be used in any size within that range. Send the species, the caliper, the canopy spread and the size you have in mind, and the combination is confirmed together with the quantity and the packing.

A filled container of this diameter is a heavy unit, and how it is handled on site matters far more than how it is handled on a bench. The load is taken on the fastened band and on the bottom, never on the open top rim and never by dragging the unit across the ground: the wall is the working part of the product and scuffing it takes the holes out of shape. A two-point lift keeps the container level, and the fastening is what holds the surrounding solid while the unit is off the ground.

At the planting position the container is set down on level ground so that the bottom sits flat and the wall stands vertical, because a unit standing out of level puts a side load on the fastening. The tree is then fixed against movement with a stake and tie, since movement at the collar while the roots are establishing is the commonest reason a tree starts badly. And because the surrounding is closed by a fastening rather than being a one-piece tub, the band can be released at the destination when the root system is ready to go into the ground.

Centres between containers are set from the finished canopy spread, so that neighbouring canopies do not touch and every tree keeps its own light. Rows are laid out with one route kept clear along the ends for the lifting equipment and for a barrow, and that route has to be wide enough for the machine that will really be used, not for a hand trolley. The ends of the rows are the natural handling points, so they are left as hard standing wherever the site allows it.

One requirement is specific to this container. The wall carries out its function through air at the holes, so the band around the surrounding is kept clear of soil, weeding fabric, gravel and stacked material: bury the wall or cover it and the air shear stops working, and the root system falls back into the circling habit the container is meant to prevent. Leave the band free over its full height, and keep the base clear so that the container can be picked up again without digging around it.

Material	Polyethylene
Economic working life	Over 5 years
Construction	Three parts - bottom, surrounding and fastening
Diameter	20 cm to 2 m
Height	20 cm to 80 cm
Dimension	Diameter multiplied by height multiplied by 3.14
Sizes	Any size within the range above

A project normally needs one size, repeated, in a quantity that follows the planting schedule. Because the unit is three parts rather than a moulded tub, the bottom, the surrounding and the fastening are supplied as the construction of the container, and a batch can be quoted for a single diameter and height or for the two or three sizes a staged programme actually uses. Working life is quoted against the programme rather than against one season, since the container is reusable and carries an economic working life of over 5 years.

Quote with the size, the quantity and the delivery date and the packing is confirmed with the order. Where a project is also ordering structures and irrigation, the containers sit alongside trays, pots and planters in the planting tools range and the greenhouse equipment and structures for the same site; a growing-on alternative for smaller stock is the PE fabric planter.

Reference material on protected horticulture and on nursery practice is published by the NGMA, and commercial nursery and landscape trade news is reported by HortWeek.

We are the manufacturer specialize in greenhouse and planting tools with above 35 years. We supply over 1,200 different kinds of planting tools. Our planting tools are widely use by farm and agricultural sciences academy and institute at home and abroad. We exported our products more than 120 different countries all over the world.

For a project order the containers are quoted with the working drawings for the block: size, quantity, packing and delivery date together, so that the lifting and layout plan and the container supply are settled at the same time.

Q: How do I match the container diameter to a particular tree?
A: Start from the root ball, not from the pot. Take the trunk caliper above the root collar and the height of the tree, and the container diameter is then chosen clear of the root ball that has to come out intact. Add the canopy spread the tree will carry when it is lifted, and the container height from the depth of the root ball. Send those figures and the diameter and height are confirmed as a pair.

Q: How is a large filled container lifted and moved on site?
A: On the fastened band and the bottom, with a two-point lift to keep the unit level. The top rim and the perforated wall are not carrying points, and the container is not dragged across the ground, because scuffing the wall takes the air holes out of shape. The fastening is what holds the surrounding solid while the unit is off the ground.

Q: What row spacing and layout should a container block have?
A: Centres are set from the finished canopy spread so that canopies do not touch and each tree keeps its light, with one route along the row ends wide enough for the lifting machine that will really be used. The band around the wall is then left clear of soil, fabric and stacked material, because the air shear only works while the holes are open to air.

Q: Can one order mix several diameters and heights?
A: Yes. The range runs from 20 cm to 2 m in diameter and 20 cm to 80 cm in height, and the container can be used in any size within that range. A staged planting programme is usually quoted as two or three set sizes rather than a single size, and the packing is confirmed with the quantity and the delivery date.

Q: What is the container made from and how long is it expected to last?
A: Polyethylene, with an economic working life of over 5 years. The material is 100% food grade with no industrial powder or reclaimed material and no foreign smell, and it is packed under a GMP standard system in a dust-free workshop, with 12 working procedures tested to hold quality steady.

Q: What condition is the root system in when a tree is lifted out?
A: According to the theory of air shear the container controls main-root cultivation effectively and improves the growth of side-roots, and it does not lead to root twisting, broken roots or injured roots during transplanting; on that basis the survival rate is over 98%. What is lifted is a branched root system spread through the volume of the container, and the fastening can be released so the band comes away rather than being cut.

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