There are a few methods for "automatically" pruning roots when growing started cutings or seedlings in pots: I've seen specially shaped pots with vents and mesh/peat pots so that any emerging roots are "air pruned", and some forestry growers paint the inside of styro molded pot flats with a latex paint/copper oxide blend. These methods are intended to (and do) increase root branching. The follow up studies indicate much increased survival and vigor after transplanting. Now the question: is anyone aware of coated or otherwise treated pots or any other brilliant options? Is it helpful to run a sharp knife around the pot from time to time? This is a question for ongoing plantings, but also specifically about several hundred (grape) plants that will have to stay in their 1 gallon pots longer than originally planned. Ralph
Ralph--Carl Whitcomb has tons of info on his root pruning products, and the theory behind them, on his rootmaker.com site. These products are not easily obtained in BC, tho McConkey's has them in their catalog and will arrange shipping (possibly no better than ordering direct from rootmaker co. in Oklahoma). Anyway, doesn't sound like these are the answer for your situation at this time. As Whitcomb would say, any plant needs to have something happen to it once every 12 mos. in a nursery--either get sold, get potted up, or get thrown out. Roots don't do so well circling round the outside of a 1 gal. or any other container, so if at all possible I would try to pot yours into 2's. Personally I get #2 pots used for 20cents from a landscaper, same as his supplier pays for returned containers. And I would use mostly potting bark so it wouldn't amount to much of an investment, just the time which could be significant if yours is as scarce as mine! On the other hand, I have lots of plants languishing here in their same container and I do expect them to live, just not take off as well as they could have had I been on top of potting them on...just in case you were thinking you were the worst plant parent around, don't worry :-) Glen