The following was received via email: I live in Kamloops and am trying to grow some grapes,(Concord I think). I bought the house a couple of years ago and the plants were in then. However since that time they have hardly grown at all. I have been giving the lots of water as well as steer manure. Is there some other fertilizer I should be using? Should I prune them back every year? Some other people I see have grapes the same age and they grow much faster. Our soil here is mostly sand and gravel. Thanks in advance for the info. Regards Bill
Hi Bill: Yes, these vines will need to be pruned preferably during the Winter. The problem is that conventional pruning of Concord and Niabell Grapes is not an accepted practice. When not trained on a trellis cordon pruning will not be effective in a Home Garden for these Grapes. We would rather train them to be staked and prune them to be more of a bush in shape instead. Concord's wood is pliable but is extremely brittle and the outer bark can crack with relative ease when worked with during the growing season allowing a entry point for a fungal or bacterial infection. Summer pruning is not a good idea unless we are quite careful and mindful of what we are doing. I suggest late Winter pruning for these. We prune our Grapes here in January. We prune the Grapes to in essence produce a larger crop for the upcoming growing season. From a physiological standpoint we want to prune the tops along with the side growth to produce more root growth and to promote plant vigor. With more root system to aid the plant the plant will better sustain itself through inclement weather but more importantly the roots will act as a storage center for nutrients when the Grapes are dormant. Right before the Grapes start to leaf out the nutrients stored in the roots will start to move throughout the plant aiding the plants overall health and help with the initiation of the plants subsequent new growth. Steer manure can be used on sandy soils as it will slow down the water infiltration rate and give rise to better water retention in the soil but I must caution you that with lots of steer manure used on a sandy soil, we tend to see a few nutrient deficiencies come about later from continued steer manure applications such as Zinc, Iron, Manganese and Magnesium deficiency. I would suggest you incorporate into the soil and add on top of the soil some forest humus (pine and/or fir bark). Unless the soil is a sandy loam, water can go through the sand almost as fast as a hot knife can through Butter. What we have to do is to limit how fast the water will soak through once it has been applied. Steer manure helps and it also is used for a its ability to act as a fertilizer. The humus will also provide a slowing of the water being soaked into the soil, will aid in the water holding capacity and will also provide some nutrients for the Grapes. I would suggest you use a commercial, granulated fertilizer for your Grapes and apply in late Winter, early Spring before the Grapes start to leaf out. Let rainfall water in the fertilizer for you and apply 1/2 to 1 pound of fertilizer per vine depending on the age of the vines. You can always fertilize again at the same rate after the vines have fully leafed out. For some of my vines here I use 5 pounds of fertilizer per vine but those vines are over 30 years old also. Any standard vegetable food from a local nursery or nursery supply store will do such as a 6-12-6 or perhaps a Tree and Vine 10-20-20 but make sure there is also Calcium in the fertilizer. A 6-10% Calcium formula included in the 6-12-6 fertilizer would be excellent for a Home Garden almost anywhere. Jim
