With longer days and warmer temperatures, it's time to start pruning grapes. Pruning grapes can be hard for gardeners. Most gardeners prune off too little, leaving a nice looking vine for now, but a monster come summer.
There are many types of pruning systems for grapes. I think the best for a home gardener growing a row of table grapes is the Kniffen system. In this system you'll need strong, six foot tall stakes, every six-to-seven feet and heavy gage wire running from stake to stake. If you use the two-arm Kniffen system, you'll only need one wire about five feet off the ground running the length of the row. The four-arm Kniffen system requires a second wire about three feet off the ground.
The first year you'll top the purchased grape vine, removing all but one strong shoot, and attach it to a vertical stake. The second year you'll top the new growth again when it reaches the wire on the two-arm system. This will force the main trunk to branch out. Tie one side cane to the wire to the left and one to the right of the main trunk. Cut these canes back to 10 buds.
The next, and subsequent years, remove last year's fruiting canes back to the main trunk. Select one replacement cane from those that grew last year. Attach it to the wire and prune it back to 10 buds. Select a second cane as the replacement cane for next year and prune that cane back to two buds. Remove all other canes on the wire and main truck of the grape.
Even though it looks drastic, you'll see that the grapes will grow back strong and produce better, while staying under control.
Now for this week's tip: check wintering dahlias and cannas in storage to see if they have started to sprout. If so, move them to a cooler spot and top the dahlias and canna lilies to slow down their growth.