The rains of July and August have promoted plant diseases, weeds, soil nutrient loss, and some pests.  While harvesting onions, potatoes, tomatoes, and other vegetables it’s important to keep weeding and begin soil preparations for next year’s garden. Potatoes, onions, and winter squashes will store better if they are “cured” in a warmer space before storing.  Pest control in Brassicas is still needed to protect our late harvests from cabbage worms and aphids.  Finally, it’s time to harvest some herbs like basil (pesto!) and dill seeds and plant some more salad greens (but not bulbs or garlic yet) for fresh fall salads.

Tomatoes & potatoes.  These plants belong to the same family and are susceptible to the same pests and diseases.  Although we have not seen any Late Blight this year, the wet days of early September have encouraged the rapid growth of leaf diseases such as Septoria and Early Blight on tomatoes.  The best practice for managing these fungal diseases is prevention by reducing conditions that favor their growth.  In tomatoes that means upright supports for better drying air flow, thinned side branches (sucker removal), straw mulch to prevent soil splashing (never water tomatoes with a sprinkler!), and regular removal of infected leaves or branches. 

It can be frustrating to try to keep ahead of the leaf infections but removing those yellowed or brown leaves slows the spreading of the diseases.  By September of wet years we may have very sparse looking plants with almost no foliage left so I’ve been leaving 1 or 2 new side shoots (suckers) to grow new foliage to help the plants mature existing fruits.  Keep snipping off new blossoms that form at the tops since those are too late to form harvestable tomatoes this season and drain energy from the plant. 

Potatoes should be harvested now, cured for 10 days, and placed in a dark storage place for winter use.  Handle with care to avoid cuts or bruises.

Broccoli, Cauliflower, Brussels Sprouts, & Cabbage.  These Brassicas (also kale, and kohlrabi) are all the same plant family and are susceptible to the same pests so can be cared for in the same way.  There are still late cabbage moths flying about laying their eggs that become cabbage worms (caterpillars) and can “skeletonize” these plants.  It’s worth controlling these pests with weekly applications of Bacillus thuringiensis (Bt, Thuricide, or Dipel) These are very safe and effective at preventing this pest.  It’s also effective for almost any caterpillar pest so avoid getting it on your milkweeds since it will be toxic to the Monarch butterflies.  Fall aphids are now appearing and can cause severe damage to this family.  The stingless hoverfly is a beneficial natural predator of aphids and should not be confused with wasps or sweat bees.  Planting buckwheat in empty spaces will attract these natural enemies of aphids.

Winter Squashes & Cucumbers.  If the leaves have died down these should be harvested and cured for 10 days in a warm room to prevent sunscald.  After curing their sugars are higher and they are ready for a cooler storage area. 

Powdery & downy mildew on squashes can be very damaging just as these plants are maturing and with cooler nights and rain.  Look for a powdery white or gray coating on the leaves.  Several methods have been shown to prevent and reduce this disease.  1) Spray a mixture of milk (1 cup milk in 2 cups of water plus ½ tsp. liquid dish soap or 1 oz. powdered milk in 2 qts. water) over the leaves every week or after rain;  2) Spray Serenade on the leaves to prevent infection;  3) Baking soda raises the pH too high for mildew to grow (1 Tbsp + ½ tsp. liquid dish soap in 1 gal. water) applied on cloudy days or in the evening.

Planting in September   Some of the best salad greens can be planted now.  Try some more leaf lettuce, mesclun, arugula, and spinach.  Plant a crop now and again next week to spread the harvest out.  As days get shorter plants slow down so it might take longer to mature but won’t tend to get bitter or go to seed (“bolt”).

Fall Bulbs… now is the time to order your fall bulbs for October-November planting.  If you haven’t grown garlic, this can be the year you start.  Order bulbs or “seed garlic” from Johnny’s Selected Seeds, FEDCO, Maine Potato Lady, or other online sources for late October planting.  The best local source for seed garlic is Caravan Gardens on Rte. 103 in Cuttingsville (caravangardens@gmail.com or 802-492-3377).  Supermarket garlic is often treated with a chemical to retard growth so isn’t recommended for planting.

Weeds.  Do not stop weeding yet!  Weeds are now producing their flowers and seeds for next year’s generation, and several generations after that.  Weeds produce from 5,000 up to 100,000 seeds per plant!  Do not allow weeds to go to seed in your garden.  One exception are the bolting plants of mustards, kale, arugula, etc. that produce shoots with small yellow flowers.  These blossoms attract beneficial predator insects (ex: hover & flower flies) that will help control insect pests in the garden and are important pollinators.

Remember to compost your food and yard wastes for the best garden fertilizer.  Here’s a short video to help you get your own compost started.  Look for the composting display and bring your questions to the Mount Holly Cider Days festival.