Grow bags: tall or squat?

[Joanne Vaughn]

After losing a planting of trees to voles/deer and now quite a number to the drought of '16 we are considering keeping our seedlings in a protected area with irrigation in grow bags so they can be easily relocated when they have attained a fighting size. 

We have been considering putting them in grow bags. Are there opinions out there about whether the root systems will be better off in fabric grow bags?

We were wondering if if is better to have a wider pot to encourage superficial root growth or a narrow pot to accommodate any tap roots?

Does this depend on species? 

Thanks for sharing.

[Kevin Mathers]

Joanne,

This preliminary information from a Colorado State study discusses fabric grow bags What Happens After You Transplant Trees

As for the shape of the bags it probably depends on your planting site soil.  If you have soil with a fragipan layer (hardpan) that restricts rooting depth, perhaps a shorter, wider bag pot would be better. During drought conditions larger transplants will still require frequent watering, so I always caution landowners to plant only what they can manage.  Hope this helps. 

Kevin

[Joanne Vaughn]

Thanks for the information. That study appears to indicate that trees developed in grow bags have a better chance of transplanting than pots or balled burlap.  There is some species differences. 

Yes we counted on the periodic rain that we THOUGHT was characteristic of our area. And the plantings to location made watering either an expensive irrigation project or a time consuming distribution project. 

I have read some other reports that give grow bags the edge: they seem to provide a less stressful root pruning, they provide better aeration and drainage and they provide a lighter tree to move to a new location.

The other thing they can provide is a choice of ball shape. Since we would be planting them into an area favoring a shallow root system (loam over high water table) it seems we should consider biasing toward a broad shallow root system. It appears that most tree species have adaptability in their root shape.

[Carl Albers]

I just started using 1 gallon Rootmaker pots that I purchased through A.M. Leonard.  The Rootmaker video on these makes sense to me...no more circling roots (there are other air root pruning brands.)  The 1 gallon size is about 7-inches deep.  I don't know how the air root pruning will affect the eventual growth of a tap rooted species like the oaks and hickories, however, much of my land has a hard pan down not too deep so I don't believe a taproot would penetrate it very much.  I could be wrong.  Other than that I don't believe the shape of the pot has much bearing on how the trees perform afterwards.  I do believe that the air root pruned "stubs" will venture outside of the planting hole better than seedlings grown in a conventional pot with circling roots.

Also from what I've read, don't place any fertilizer in the planting hole or any sod you've removed from the planting hole.  Fertilizer in the planting hole encourages the roots to stay there, certainly a problem when drought strikes.  I always water each tree I plant during the first growing season; frequency depends on how much rainfall and the size of the tree planted...bigger trees need to be watered more often.  Weed control is essential; especially grass control.

[Joanne Vaughn]

I will be interested to hear how your Rootmakers work for you. I think the idea with them is to make a healthy root system by encouraging roots to grow out at all depths. I think the grow bags trap the rootlets and then when the plant is moved to a larger container all the rootlets are clipped and so that cutting causes the roots to generate a denser mat of  non circling roots. 

Stark Bros say they have EZ pots and trim the tap roots of nut trees to allow them to be transplanted easier.

http://www.starkbros.com/growing-guide/article/an-ez-start-to-growi...

[Carl Albers]

I like the dimensions on the Stark Bros EZ pots, but wish they had incorporated air root pruning on the sides of the pots in addition to the bottom.  Their pots should take care of the taproot, but I think air root pruning on the sides would produce an even better root system?