The rainy weeks of August have promoted plant diseases, weeds, and some pests.  As harvesting of onions, potatoes, tomatoes, and other vegetables continues it’s important to practice prevention to limit damage to our hard-earned harvests. While harvesting veggies, herbs, and flowers is the best part of gardening, don’t overlook another crop you might want to gather… seeds for next year.  If you’ve grown peas, beans, tomatoes, or lettuce these are the easiest to save and assure you will have good seeds for next year.  There are many advantages to saving your own seeds and it’s very satisfying to see your plants through from generation to generation.  Sort of like your botanical grandchildren.  It’s also time to harvest some herbs like basil and dill seeds, plant some more salad greens (but not bulbs or garlic yet) and learn about a new way to identify wildflowers and weeds.

Tomatoes & potatoes.  These belong to the same family and are susceptible to the same pests and diseases.  Although we have not seen any Late Blight yet this year, the wet days of August 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 vary sparse looking plants with almost no foliage left so I’ve been leaving 1 or 2 new side shoots to grow new foliage to help the plants mature exiting fruits.  Keep snipping off new blossoms that form at the tops since those are too late to form harvestable tomatoes and drain energy from the plant. 

One more practice to prevent (not cure) leaf diseases is to apply foliar copper or sulfur to block the growth of new infections of healthy leaves.  These are acceptable Organic fungicides and I alternate these weekly along with liquid fish emulsion fertilizer in the mix.  New studies have indicated that compost tea applied to leaves also reduces infection.  All of these can be safely applied to all vegetables, fruits, and flowers.

Broccoli, Cauliflower, & Cabbage.  These Brassicas (also Brussel sprouts, kale, and kohlrabi) are all the same plant and are susceptible to the same pests so can be cared for in the same way.  There are still some cabbage moths flying about laying their eggs that become cabbage worms (caterpillars) on these plants.  Whether you are still harvesting from earlier plantings of late plantings for a fall harvest it’s worth preventing these pests.  I’ve found that weekly applications of Bacillus thuringiensis (Bt or Dipel) is 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.

Seed Saving.  Gardeners and farmers have traditionally saved seeds from their favorite plants because we know that is the best way to have the best varieties and strains adapted to your local conditions.  Seeds contain the genes of the parent plants and if you have a favorite heirloom tomato, bean or lettuce that does well for you why not save some seeds for next year?  Besides, they are free and abundant right now!  Seed Savers Exchange has been promoting seed saving for many years and offers very practical advice for beginners.

Not all plants lend themselves to the home seed saver.  I recommend the “self-pollinating” plants (beans, peas, lettuce, tomatoes, peppers, dill, arugula, sunflowers, & parsley) are mostly foolproof.  I would avoid insect/wind pollinated plants (corn, squashes, cucumbers, pumpkins, & melons) because they are considered “promiscuous” as they cross pollinate, and most offspring will not be the same as the parents.  Hybrids (F₁) varieties are also in this category and are not reliable for seed savers.  If you really want to learn more about the wonders of seed production and saving then I recommend the book The Seed Garden. 

Seed savers divide seeds into “dry seeds” and “wet seeds” because they use different methods to prepare them for storage.  Dry seeds (lettuce, arugula, beans, & peas) are easiest because we simply need to let the seed pod or bean mature fully until it turns yellow-brown and dries on the plant.  Before it pops open collect the pods/beans for more drying before storing.  Even though these seeds may appear dry, they require thorough drying so they don’t get moldy in storage over winter.  After collecting seeds (get more than you need so you can share some) lay them out on newspaper in an airy, protected location for a couple weeks.  Beans & peas especially needs extra drying time. Once dry you can separate off the pods or chaff by gently blowing it away from heavier seeds. This is an excellent use for those neglected lettuce plants that went to seed.  Don’t worry about small bits of debris in the seeds.

Wet seeds (heirloom tomatoes & peppers) are removed from over-ripe fruits to be sure the seeds are mature.  Pick the most desirable plants for your seeds (earliest, biggest, high yielding, pest & disease free, etc.) so you select the best next for year.  Cut open the fruits and scoop out the biggest seeds for drying.  Spread them out on a baking tray for drying at room temperature.  Gently mix them every couple days to keep them separated as much as possible.  Once they’ve dried completely, collect them for storage.  Remember that hybrid seeds will not breed true so are generally not worth saving.

Storage containers can be anything that will protect the seeds from moisture, heat, mice, light, etc.  Glass jars, empty medicine bottles, zip lock bags (in a larger glass jar), etc.  Most important:  LABEL every container/bag/bottle with the plant name, variety, and date stored.  Keep your saved seed (plus leftovers that you purchased this year) in a cool, dry, dark place over the winter.  Not in the refrigerator or freezer.

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.  Many are already out of stock. The best local source for seed garlic is Caravan Gardens on Rte. 103 in Cuttingsville (farm stand open Wednesdays and Saturdays).  Supermarket garlic is often treated with a chemical to retard growth so isn’t recommended for planting.

Pest Alerts:  Insect pests are slowing down now but there still may be late season Japanese Beetles and Stinkbugs (handpick them) along with moth caterpillars about.  Tomato Horn Worms have been very active this season so double check your tomato plants for those extra large green caterpillars.  Look for leafless side branches or big droppings on leaves as a sure sign.  They’re easy to pick off and dispatch with pruning shears or soapy water.

Powdery & downy mildew on squashes can be very damaging just as these plants are maturing their production and it will increase with cooler weather 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.

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 are known to 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.

Know your plants.  If you are interesting knowing the names of those weeds and wildflowers around your yard there is a great smartphone app called Seek that will quickly identify almost any plant simply by pointing your phone camera at the blossoms or leaves.  No need to take a photo or submit it online.  I’ve found it works well without any internet connection but you can upload your images later if you want to keep a record of what you’ve found.  The app is available for FREE at Google Play or Apple Store and is very easy to use.

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.

What are you seeing on in your garden?  Got questions?  Suggestions? Leave a message in the Comments below.