Peterborough & Area Master Gardeners

Q: My blackcurrant bush has developed orange spots on the underside of the leaves. The leaves are starting to drop off. What should I do?
A: In early spring, spray with a dormant oil/lime sulphur wash and spray again afler harvest with lime sulphur. Destroy all infected leaves and infected plant debris. Do not compost them. The rust fungus spends part of its life cycle on white pine, but needs the currant to complete this cycle. Therefore, do not plant white pine and currants in close proximity as the cycle will keep repeating itself

Q: What do grapes require?
A: They need a well-drained area that receives a minimum of half a day's light. Full sun is preferential. They also require regular and proper pruning. Protection from the winter should be provided by laying the vines down and covering them with 3 to 4 inches of soil. They will require a trellis of some sort during their growing season. Pruning Rules: Prune all crippled branches; Remove Branches growing either straight up or straight down; Make clean cuts; Avoid leaving o stub; Prune annually; generally in the spring just before new leaves appear.

Q: Please name a blueberry bush I can plant that is hardy to colder climates (i.e. North Bay):
A: Try Rancocas. This variety will ripen early and is suitable where the growing season is short. It produces medium-small berries which are flavourful. But choose more than one variety. Cross-pollination will aid in larger and more plentiful fruit. Another suggestion is Northland (a hybrid).

Q: How do I prune my elderberry?
A: Take out the older branches and any that were questionable last year right to the ground. Do this before they bud out in the spring. You should be taking out some older stems each year in late winter early spring. Ideally you should have an equal number of 1, 2 and 3 year stems.

Q: If fruit trees fail to bear fruit, what could be wrong?
A: Many fruit trees require at least one other variety planted nearby, which blooms at the same time, in order to cross-pollinate each other. As well, your trees may not be old enough yet to bear fruit. Peaches and sour cherries require approximately 3 years; sweet cherries need 5 to 7 years. Spring frost could be killing off the flowers. Prolonged cold, wet weather in spring will also affect the tree's ability to set fruit. Poor drainage, lack of nitrogen or injury because of disease or insects are also factors.

Q: How can I get rid of the lilac suckers without using any toxic chemicals?
A: The only way to get rid of lilac suckers is to keep cutting them out from the base of the shrub. Cut as close as you can to the main stem. If there are rooted suckers further away from the main bush, they will need to be dug out.

Q: What vegetables can I start indoors to get a jump on the growing season?
A: Cucumbers, squash, melons, lima beans and tomatoes are some good choices. All large seeds may be sown directly into individual cells or jiffy pots. Harden the seedlings off and plant outside after all danger of frost is past in your area. Smaller seedlings transplant better with less shock than bigger plants -and they're cheaper!

Q: What is tomato mosaic virus?
A: The lower leaves of tomato plants fall off while fruit continues to form well. Often started by smokers touching plants/seedlings. Once established, it is then aggravated by wet weather and is spread by water splashing from leaf to leaf. Drip irrigation to reduce spread; rotate crops yearly; mulch around plants to prevent splashing; wash hands in a weak bleach solution before handling plants.

Q: There are still some unripened tomatoes on the vine in the fall. Will this fruit ripen if I pick it?
A: This fruit will ripen if you follow a few guidelines. First, it is very important to pick this fruit before the temperature becomes too cool (at the bright green stage and when temperature is approximately 50 degrees F). If the temperature drops too low, the fruit will not ripen no matter what coaxing you give it. Lay fruit out individually, cover with moistened newspaper, store in dark and at 54-75 degrees F. Check frequently for ripeness and molding. A tablespoon of Epsom Salts around each plant monthly will add much needed magnesium. Eggshells, crushed and scattered around plants adds calcium. Eliminates blossom end rot. AVOID high Nitrogen (N) fertilizers as leaves and vines will be the main crop as a result. High Potassium (K), low Nitrogen (N) (4-10-20) would be ideal.

Q: How can I prevent cauliflower heads from turning yellow?
A: By taking the outer leaves and tying them loosely around the head to keep the light out. The sunlight will cause the heads to turn yellow.