Life Outside the City Limits
- Pumpkins - Harvesting & Storage
- Nutty About Nut Trees
- October Turf Tips
- Frost - Cold Temperatures Bring an End to the Gardening Season
- Plants for Dry Sites
- Pond and Lake Management - October Question & Answer
- Sediment Filtration for Private Drinking Water Supplies
- Thistle Control During October
- Winter Pesticide Storage
For a complete listing, visit the
Upcoming Events Calendar
Pumpkins - Harvesting & Storing
By Nicole Stoner, Nebraska Extension Educator - Horticulture
The trees are beginning to turn beautiful fall colors, leaves are beginning to fall and scary movies are starting to come back into the theatres. This must mean Halloween is on its way.
The best part of Halloween, to me, is the pumpkins. I love the smell of a freshly carved pumpkin and the look of the carved pumpkins on my front steps lit up for Halloween night. Pumpkins can be used for a variety of things throughout October and November, and they can be grown right in your own backyard garden.
Pumpkins are a member of the cucurbit family, which includes cucumbers, squash, gourds, watermelons, cantaloupes, and zucchini. We use them for eating, roasting the seeds, and carving for a Halloween decoration. We can also store them and use them for Thanksgiving decorations.
If you grow pumpkins in your garden, it is now time to begin harvesting them, if you haven’t already started. Pumpkins can be harvested when they are mature in color and when they have a firm rind, when your fingernail does not puncture the rind easily. It is best to remove all pumpkins prior to or within 1-2 days after a killing frost. Cut pumpkins off of the vine leaving 3-4 inches of stem attached to help the pumpkin resist decay organisms.
After the pumpkins are harvested, they should be cured enabling them to last longer in storage. Leave pumpkins in an area where they receive 80-85 degree temperatures with 80-90 percent relative humidity for 10 days. Pumpkins will store if not cured, but they will store longer, up to 3 months, if they are cured first. After cured, they are best stored in areas of 50-55 degree temperatures.
To Carve or Cook?
It is best to use the correct pumpkin for the task, such as using a jack-o-lantern pumpkin for carving and a processing pumpkin for making pies. Both types of pumpkins can be used for either activity, but they work better if you get the right type for the task at hand. However, you do not want to carve a pumpkin and use it for Halloween and then use it for making a pumpkin pie. A carved pumpkin is a perishable item, therefore cannot be used for baking or cooking if it has been left out, after being carved into, for more than 2 hours.
Many people are concerned about the length of time a carved pumpkin will last on their front porch. The problem is that there isn’t a good treatment to get them to hold that carving for very long. The best idea is to wait until no more than one week before Halloween until you carve your pumpkin. It is best for the carving if you can do it as close to Halloween as possible.
Another thing that will help with longevity of a pumpkin for Halloween is to ensure that you purchase or pick a pumpkin in good condition. Avoid pumpkins with soft spots, signs of decay, short stems, and other signs to show that decay has already begun in the pumpkin. If decay is already present in the pumpkin before you carve into it, it will ruin your carving that much sooner.
If the weather is warm outside, store the pumpkins in a cool area until Halloween to keep the carving intact. Hopefully all of these tips can help you grow a great pumpkin and have a great pumpkin for Halloween. Happy Halloween!
Nutty About Nut Trees
By Justin Evertson, Nebraska Forest Service
When someone is said to be a “tree nut,” it means they really like trees and are probably a bit obsessive about them. If you’re not that into trees, you may not want to sit by a tree nut at a social function. You’ll likely hear that some trees can reach over 300 feet tall and that some are over 5,000 years old. And you’ll probably hear quite a bit about many of the over 200 different kinds that can be grown in our region—a region once dominated by prairie.
I’m a tree nut. In fact, I’m especially nutty about nut trees, including hickories, pecans, walnuts, buckeyes, chestnuts and just about any other tree that could produce a fruit that a squirrel would love (most tree nuts are not squirrel nuts). This little article celebrates hickories—the king of the nut trees. Though they’re seldom encountered in the planted landscape, hickories most definitely deserve greater attention and planting.
The word hickory derives from the Algonquin or Powhatan word pohickery. Their scientific name Carya is Greek in origin and means “nut.” Hickory species occur throughout the eastern U.S. and most were important food or timber sources for Native American tribes and early settlers. There are five hickory species native to the Midwest (two are native to Nebraska’s eastern hardwood forests) and they all have very descriptive common names, usually relating to their nuts or their bark.
Bitternut hickory (Carya cordiformis). As its name implies, this hickory has a small, bitter-tasting nut. This is Nebraska’s most common native hickory occurring in oak-hickory woods from the South Sioux City area southward to Jefferson County. It’s a fast-growing hickory that can reach up to 70 feet tall and 30-40 feet wide. Bitternut turns a nice yellow in the fall and is easily recognized in the winter by its smooth young bark and sulfur-yellow buds.
Shagbark hickory (Carya ovata): This hickory is known for its “shaggy” bark, which exfoliates in long strips as the tree matures. Unlike the bitternut, the shagbark has a relatively tasty nut favored by a wide variety of forest birds and animals, as well as humans. The tree has large, deep green, compound leaves that can turn a bright yellow in fall. The shagbark reaches 50-60 feet tall and is relatively abundant on rich soils in Nebraska’s oak-hickory woods from the Omaha area south to the Rulo Bluffs.
The shellbark hickory (Carya laciniosa) is a close cousin of the shagbark hickory, possessing the same “shaggy” bark. Sometimes called the kingnut, shellbark has the largest nuts of all the hickories, which while still in the outer husk are about the size of a baseball. The nuts are sweet and tasty and highly prized by both humans and wildlife. Shellbark can grow quite large, from 60 to 80 feet tall and up to 50 feet wide and is one of the longest-lived hickories. Though not native to Nebraska, there are many impressive specimens in southeastern Nebraska.
Mockernut hickory (Carya tomentosa) is perhaps the most common hickory of the eastern U.S. Its common name refers to the relatively large nuts that have thick shells and very little nut meat inside, thus “mocking” those that try to eat them. Mockernuts grow straight and true, up to 60 feet tall or more, and can be very long-lived, with some specimens known to be over 500 years old.
Northern pecan (Carya illinoinensis) is related to bitternut hickory, with the two species sometimes producing naturally-occurring hybrids where they occur together. Unlike the bitternut, the pecan has a very tasty nut that has become an important food crop across the world. In fact, the pecan is the most abundantly harvested food crop native to North America. Almost every other modern food crop originated on other continents. Pecans make great shade trees with many in eastern Nebraska reaching up to 80 feet tall and 60 feet wide.
Most hickories possess a thick and deep-growing taproot that makes them somewhat difficult to transplant and which also makes them relatively rare in the nursery trade. That’s too bad. The hickories are great trees in a lot of ways: they provide good shade; they’re generally long-lived; they provide good lumber; they support a wide variety of important wildlife; and they often have tasty nuts.
Do yourself a favor and seek out a hickory or two for planting in your own yard. It can be as simple as going out into the native woods and harvesting some nuts that the squirrels have missed. Alternatively, many on-line nurseries offer hickories, including the Nebraska Statewide Arboretum. It is generally recommended to plant small seedlings. Finally, a great organization to learn all about nut trees, including grafting, planting and harvesting is the Nebraska Nut Growers Association. Talk about a great bunch of tree nuts!
The Nebraska Forest Service strives to enrich lives by protecting, restoring and utilizing Nebraska's tree and forest resources.
October Turf Tips
By John Fech, Nebraska Extension Educator - Horticulture
Many property owners focus on spring lawn care and are in the mode of “just mow it” as far as the fall is concerned. As with most things in life, you get out of it just what you put into it and turf care is no exception. Fortunately, the list of “to-do”s is shorter in October than it was in April and September. In this month, we’re focused mainly on broadleaf weed control and falling tree leaves.
Broadleaf weed control starts with proper fertilization, irrigation, cultivation and pest control, with the goal of growing a healthy lawn. A thick, dense lawn is the best weed control that anyone can provide for the lawn, as it shades the soil and greatly reduces weed germination. It’s always easier to prevent weeds than to control them.
In the endeavor of controlling broadleaf weeds such as plantain, spurge, false strawberry, creeping Charlie and dandelions, early October is the preferred timing. Why? Many reasons:
- Translocation is high within the plant, as nutrients are being moved downward into the root system for the summer.
- Flowering is less, which means that the weeds are more likely to absorb the herbicide rather than put their energy into producing flowers.
- Many veggie gardens and annual plantings are winding down for the season, thus the consequences of a bit of herbicide drift are lesser than if it occurred earlier in the year.
- Herbicide applications made during cool to warm conditions will control weeds but won’t burn the turf.
Spot treatment applications are preferable over “weed and feed” products, as they specifically target the weeds, avoiding unnecessary product being spread over the entire turf surface. As with any weed control effort, at any time of year, be sure to read and follow all label directions, as they provide helpful instructions as to the effectiveness and safety of the application.
Utilizing Fall Leaves
Trees are the stalwarts of a landscape, but from time to time, almost all trees produce undesirable issues to be dealt with. In fall, leaf debris that drops must be handled in one way or another. Perhaps a paradigm shift is in order. Instead of thinking of falling leaves as a waste product, try considering them to be a resource. As such, two options exist for utilizing them – picking them up with a rake or lawn mower bagger and placing them on the compost pile, and chewing them up with a mower and recycling the nutrients directly back to the lawn.
If the leaves, fruits and twigs are really bothersome, consider redesigning the landscape to create less debris. This is best done in consultation with a landscape designer, utilizing the principles of mass/void, separation of turf and ornamentals, layering, right plant, right place and unity in mind.
Frost - Cold Temperatures Bring an End to the Gardening Season
By Sarah Browning, Nebraska Extension Educator - Horticulture
Eastern Nebraska has been lucky so far - no frost or freezing temperatures yet this fall. But we all know it’s coming soon. Of course, we're at the end of the gardening season. But if you have tender plants you want to keep growing for a while longer, its important to pay attention to weather forecasts and provide protection if freezing temperatures threaten.
The average first fall frost date for Lancaster County is about October 10th; between October 6th and 9th to be specific. These dates are determined from over 47 years of weather data, starting in 1949. It’s a good guideline to estimate when frost will occur, but since this is an average first fall frost date, half of all autumn freezes will occur before these dates and half will occur after.
What is Frost?
Frost is the formation of small ice crystals on a surface, like leaves, petals or grass. To understand frost formation, you also need to understand dew point. The term “dew point” is the air temperature at which air is fully saturated with water vapor, so water is evaporating at the same rate as it is condensing.
When the temperature of a surface, like a leaf, falls below the current dew point of the air, water begins to condense on the leaf surface. Dew on grass and plant leaves is a common occurrence, but when the leaf surface temperature is also below freezing the water transitions directly to white ice crystals as it condenses on the leaf.
If the air is very dry, visible frost may not form even if air temperatures fall below freezing
Gardeners know to protect plants from frost and freezing temperatures when a cold arctic storm front moves through. But more commonly, the first fall freeze occurs on a clear, calm night when air temperatures simply drop below freezing. No storm or gusty winds. Under these conditions, the garden's soil surface cools quickly since there is no cloud layer to hold warm air close to the ground. The soil's heat is lost to the air above and cold air develops near the ground. This layer of cold air closest to the ground causes damaging frost on your plants. This is called an advective freeze.
Understanding Freeze Damage in the Landscape
Seeing frost on plants in the morning is an indication temperatures have gotten cold enough during the night to cause water to freeze. The frost itself on plant surfaces does little damage, but freezing of water inside the plant can cause significant damage. Think of what happens when pipes freeze in a house. Cell walls are collapsed as water between plant cells freezes.
The most important factors in plant damage are 1) how cold did temperatures get, and 2) how long did the temperatures stay below freezing. Low temperatures that persist for longer periods of time cause the most damage.
Preventing Frost Damage
Cold air from an advective freeze moves to the lowest areas of the landscape and "pools" there. This makes plants in low areas more susceptible to freeze damage than those in higher areas. When frost is forecast, concentrate your efforts on the warm-season plants or crops you want to save that will be injured by cold temperatures.
If you still have produce in the vegetable garden, consider the cold hardiness of these crops.
- Very hardy
- Can withstand freezing temperatures and hard frost (less than 28° F) for short periods without injury.
- Asparagus, collards, endive, kale, kohlrabi, lettuce, mustard, pea, potato, rhubarb, rutabaga, salsify, spinach, turnip
- Frost tolerant
- Can withstand light frosts (32-28° F) without injury.
- Beet, broccoli, Brussels sprout, cabbage, carrot, cauliflower, celeriac, celery, chard, Chinese cabbage, Jerusalem artichoke, onion, parsnip, radish
- Injury or killed by frost (32° F).
- Snap bean, sweet corn, tomato
- Warm loving
- Cannot tolerate cold temperatures.
- Lima bean, cucumber, eggplant, muskmelon, okra, pepper, pumpkin, summer squash, winter squash, sweet potato watermelon
Providing Frost Protection
A. Cover plants - Low-growing crops such as cucumbers and prostrate tomatoes are easy to cover with straw, newspapers or old bed sheets. Caged tomatoes and pepper and eggplant plants can be covered with paper grocery sacks or plastic trash bags.
The aim of covering plants is to trap heat from the soil in the air immediately around plants. It's important to uncover them the next morning, especially if you used plastic to fend off the frost. Plastic will trap the sun's heat the next day and plants may cook.
B. Finish your harvest before frost comes - Harvesting when frost threatens is another option. Whether you rush to pick your produce before frost depends largely on the crop, how you intend to use it and how soon you can use it if it does get frosted.
- Winter squash and pumpkins intended for storage should be harvested before frost because frost will damage their rinds and shorten their storage life. If they do get frosted, harvest them within a day or two and cook, freeze or can them immediately.
- Green tomatoes picked before frost can be stored at 50 to 55 degrees F and ripened for weeks. Those picked after frost will not ripen or keep long, however.
- Pepper plants turn black with frost and the fruits quickly turn mushy and rot. If you can't cover the plants, pick the peppers before frost.
- Though bean plants are killed by frost or a hard freeze, the pods do not show damage right away. Pick and use or process them as soon as possible, however, for a quality product.
- Summer squash plants wilt dramatically and fruits deteriorate quickly after freezing or frost. Pick summer squash before frost.
- The cole crops -- broccoli, cabbage, Chinese cabbage, cauliflower and Brussels sprouts -- will tolerate quite a bit of frost. Though a really hard freeze will reduce the keeping quality of even these hardy vegetables, it's not necessary to rush to cover or harvest them when frost threatens.
Plants for Dry Sites
By Christina Hoyt, Nebraska Statewide Arboretum
In a year of ample moisture it’s easy to forget Nebraska’s tendency towards drought. Choosing plants that can withstand dry conditions saves water and makes the landscape more resilient to dry times. And most landscapes have a place where it is dry no matter how much moisture we get, whether it’s under a big tree or in a “hell strip” surrounded by concrete.
There are several common dry situations that are difficult no matter what is planted in them:
- Dryer vents blow excessively hot air on plants, scorching the leaves and drying out both plants and soil. If you are trying to screen the vent with plants, extend the bed out as far as possible or consider screening with non-plant material.
- Dense canopies/shallow roots: Maples, spruces or other trees with dense shade and/or shallow root systems are difficult to plant under. Consider mulching to the drip line and planting herbaceous or woody plants farther out from the dripline.
- “Hell strips” surrounded by pavement: These areas get both direct and reflected heat and frequently have poor drainage. In winter, de-icing chemicals and snow loads can also be a problem. Raising the soil grade slightly and adding organic matter can help with drainage and it’s best to choose plants that can tolerate salt.
Blonde Ambition blue grama is an improved cultivar of native blue grama with showy seedheads standing almost 2 feet high, a foot and a half taller than the straight species. This plant wants dry, well-drained soil.
Little bluestem. People often shy away from this great Nebraska native because it can flop in the landscape but usually the reason it flops is that it receives too much moisture, either from purposeful watering or overspray of turf irrigation. Plant it high and dry and it will stand 3-4 feet high and provide beautiful fall color and texture.
Dotted gayfeather is the most drought-tolerant of the gayfeathers, with roots extending deep in the soil. In late summer the stiff flowering spikes are 2 feet high and covered with feathery clusters of purplish-pink flowers. Each plant has a corm that can live for decades and give rise to dozens of flower stalks each year. This is a tough plant that thrives in summer heat.
Dwarf leadplant is a great low-growing species of leadplant with gray foliage and magenta purple blooms. It’s slow to get established but extremely long-lived once it is.
Catmint. Yes, yes. This plant is everywhere along curbside plantings and there is a reason! It loves it dry and is stunning in the spring. Cut it back to get more blooms in the fall.
Plumbago produces a dense growth of glossy green foliage, making it a fine groundcover for sunny areas or in afternoon shade. The intense, gentian blue flowers start appearing in late July and last into fall when the foliage turns a bronzy red, contrasting nicely with the flowers.
Sedges. There are several sedges that prefer dry conditions. In sunny areas, try brevior sedge which has great form and glossy foliage. In shade, try oak sedge with a beautiful fountain form and glossy foliage.
Pawnee Buttes sandcherry is a low-growing cultivar of sandcherry with beautiful glossy, grey-green foliage and a spreading habit. It is not very long-lived but can handle heat and drought better than most shrubs.
Mohican viburnum is a common cultivar of lantana viburnum growing 7-9 feet high and wide that’s quite drought-tolerant and has thick, leathery leaves.
Chokeberry cultivars vary in size. They have glossy, dark green foliage turning orange to red in fall and healthy, edible aroniaberries. It’s very adaptable, handling sun to shade and moist to dry conditions.
Snowberry grows 4-5 feet high and wide in sun to part shade. It has an arching habit and small leaves. Its best season is fall, when it’s loaded with white berries, or try the cultivar Amethyst with berries blushed in pink.
Nebraska Statewide Arboretum is a nonprofit that works toward sustainable home and community landscapes through initiatives in education, public gardens and the environment. Plant and landscape resources at http://arboretum.unl.edu.
Pond and Lake Management - October Question & Answer
By Katie Pekarek, Nebraska Extension Educator and Mike Archer, Nebraska Department of Environmental Quality
Question: My pond has a lot of algae on the water surface. Why does this happen?
Answer: Aquatic vegetation, including algae, provides food, nesting sites, shade, and cover for many aquatic species. It also oxygenates the water and can minimize shoreline erosion and wave action. Excessive amounts of aquatic vegetation cause a variety of problems in a pond, from upsetting the balance in the fish population to creating a potentially toxic situation for humans and animals. There are several factors that contribute to excess algae and plant growth, including:
- A high nutrient level, usually phosphate. This is usually the result of nutrient-loaded runoff from crop fields, pastures, goose droppings, lawn fertilizer, or excessive amounts of leaves and other organic matter.
- Stagnant water. A lack of wave action or water movement from the watershed that encourages growth, especially if nutrient levels are high.
- Small pond size or shallow depth. These conditions more apt to promote excessive plant growth than a large size or greater depth.
- A low water level in the pond. This limits wave action and agitation from the wind. Additionally, lower water levels and shallow depth allow for an increase in the temperature of the water which can encourage certain types of algal growth.
There are several methods for reducing excess aquatic vegetation, including physical treatment, chemical treatment, biological treatment, installing a pond liner, water level manipulation, dredging, and shading, but the best long-term solution is to reduce the amount of nutrients entering the pond.
Sediment Filtration for Private Drinking Water Supplies
By Bruce Dvorak - Nebraska Extension Environmental Engineering Specialist and Sharon Skipton – Nebraska Extension Water Quality Educator Emeritus
Do you have a sediment filter to treat your private drinking water supply? Learn more about sediment filters below.
A sediment filter removes suspended material such as sand, silt, loose scale, clay, or organic material from water. These materials can be the cause of turbidity or cloudiness in the water.
Function of Sediment Filters
In addition, sediment filters often are used in combination with another drinking water treatment method for removal of contaminants such as dissolved iron, manganese, or hydrogen sulfide. In this situation, filters are used after aeration, ozonation, or chlorination which oxidizes dissolved iron, manganese, or hydrogen sulfide into solid particles that the filter then traps. Sediment filters also are used as pretreatment for other processes such as activated carbon filtration and reverse osmosis to increase their effectiveness.
Sediment filters alone do not effectively remove nitrate, heavy metals, or pesticides. Occasionally drinking water may contain very fine suspended material, sometimes referred to as “flour sand,” or very fine clay particles, which may be too small to be removed by typical sediment filtration.
Sediment filters may be installed as Point-of-Use devices that can be installed under the sink, attached to a tap, or used as a pre-filter for other water treatment processes to increase their effectiveness and longevity. In cases in which sediment may be an issue with water-using appliances, sediment filters may be installed as Point-of-Entry devices that treat all water at its entry point into the home.
Types of Sediment Filters
Sediment filters consist of a housing, usually plastic, surrounding the filter medium. Plastic housings for different filters often look about the same. The filter material in the housing determines the filter’s function and effectiveness. The filter medium can be made from a variety of materials. Common materials are paper, ceramic, polypropylene acrylic fiber, glass fiber, polyester, spun cellulose, and rayon. Wrapping or corrugating the material creates a larger filter surface area for contact with untreated water.
In the sediment filtration process, pressure from the water line forces the water through the media, or fiber wraps of the medium, into the inner cylinder, which leads out of the filter to the water line. Contaminants strained from the water are retained on the surface of the medium or are trapped with it.
Filter Pore Sizes and Ratings
The size of particles retained depends on the pore size or the space between media fibers or granules. Most filters list an average pore size and are rated by the manufacturer according to the smallest particle they can trap. For example, a 10 micron filter would trap contaminants 10 microns in diameter or larger. Check the filter rating before purchase to make sure it will trap the particles you want to manage. Sand particles range in size from 50 microns to 2 millimeters while silt particles average 2.0 to 50 microns.
Filter pore sizes that are larger than a targeted contaminant will allow that contaminant to pass through. Some clay particles, which generally range from 0.2-2.0 microns, are too small to be removed by typical sediment filtration. A microfiltration process that uses a membrane with smaller pore sizes to remove particles of 0.02-2.0 microns may be more effective in such a situation.
But a smaller pore size is not necessarily better. If the pore size of the filter medium is too small or if the concentration of suspended solids in the water is too high, the filter may easily clog and require frequent replacement. In general, the largest rating size that will remove the contaminants being managed will require the least maintenance.
Filter ratings may additionally be rated as either “nominal” or “absolute.” Those rated “nominal” should trap approximately 85 percent of particles equal to the pore size rating, while those rated “absolute” should trap approximately 99.9 percent.
Eventually, the filter medium must be cleaned or replaced. Some cartridge filters are rated according to the number of gallons of water they can treat. While this is a helpful guideline, differences in the type and amount of contaminants in the water make it difficult to accurately predict how much water a filter will effectively treat. If a noticeable drop in water flow through the filter occurs, the cartridge needs to be cleaned or replaced.
In some cases, bacteria can accumulate on filters, particularly those with paper medium. Though these bacteria may not cause illness, they can contribute to other water quality problems such as offensive taste or odor and corrosion. If bacterial growth occurs on a paper media filter, consider using a nonbiodegradable material.
For additional information on sediment filtration, see the Nebraska Extension NebGuide “Drinking Water Treatment: Sediment Filtration."
Thistle Control During October
By Monte Stauffer, Nebraska Extension Educator - Livestock
Many pastures where we graze our livestock had some thistles growing this year. If there were thistles this year, there will probably be thistles next year unless you take action this fall.
Timing is everything. That’s particularly true with thistle control and October to early November is one of the best times to use herbicides.
Did you have thistles this year? If so, walk out in those infected areas this week. I’ll bet you find many thistle seedlings. Most thistle seedlings this fall will be small, in a flat, rosette growth form and they are very sensitive now to certain herbicides. Spray this fall and thistles will not be a big problem next year.
Several herbicides are effective and recommended for thistle control. Maybe the most effective is a newer herbicide called Milestone. Two other very effective herbicides are Tordon 22K and Grazon but be careful since they also kill woody plants, including trees you might want to keep. 2,4-D also works well while it’s warm but you will get better thistle control by using a little less 2,4-D and adding a small amount of Banvel to the mix. Other herbicides also help control thistles in pastures – like Redeem, Ally and Curtail. No matter which weed killer you use though, be sure to read and follow label instructions, and be sure to spray on time.
Next year avoid overgrazing your pastures so your grass stands get thicken and compete with any new thistle seedlings. Give some thought now to thistle control during October and November and your pastures can be cleaner next spring.
Winter Pesticide Storage
By Clyde Ogg, Nebraska Extension Educator - Pesticide Safety
What, if anything, should be done with any herbicides, insecticides and fungicides leftover from the summer growing season? And if pesticides freeze, will they still be good next year?
The first rule of thumb is to check the product label for storage recommendations and any warnings against freezing, said Most liquid pesticides may be safely stored between 40F and 100F.
If a liquid pesticide does freeze, it may be less effective. Apply a degraded pesticide next year, and you have just wasted your time.
Pesticides contain active ingredients and inactive ingredients. The active ingredient is what kills the pest. The inactive ingredient is normally the solvent, carrier or emulsifier that make the pesticide more efficient.
University of Missouri Extension “Temperature Effects on Storage of Agricultural Products” says the freezing point of many pesticides is lower than 32F, due to the hydrocarbon solvents or inert ingredients. However, when a liquid pesticide freezes, the active ingredients can separate from the solvents or emulsifiers. Freezing can cause the emulsifiers to become inactive, crystalize, and coagulate.
Some pesticides may be thawed naturally at room temperature – never with a flame or heat -- after being frozen. Make sure the container has not cracked. After thawing, roll and shake the container to resuspend the contents.
If crystals are still present after thawing, the pesticide should not be used as it will be ineffective, and could plug the sprayer. Rather, dispose of properly according to label directions.
Generally, wettable powders and granules aren’t affected by low temperatures. Moisture, though, can cause caking that may reduce effectiveness. Products formulated in water-soluble packets should not be frozen as they will become brittle and break open.
Follow these general pesticide storage tips:
- Don’t store near heat, sparks or open flames
- Avoid contaminating other pesticides, water, feed or fertilizer.
- Keep containers tightly closed in a cool, locked, well-ventilated place away from children and pets.
- Store in original containers only.
- If storage information cannot be found on the label, contact the pesticide manufacturer.
To keep your sprayer in good condition, follow these sprayer storage suggestions from G1770, Cleaning Pesticide Application Equipment.
- Wear personal protective equipment.
- Before storing the liquid sprayer for winter, ensure it is completely empty and clean. As much as 15 gallons of product can remain in the tank after it's been emptied, due to the volume in the lines and filters.
- When storing, add one, and up to five, gallons of lightweight oil such as diesel fuel or kerosene before final flushing. This applies a protective coating on the inside of the tank, pump and plumbing.
- Store in a clean, dry building. If the sprayer must be stored outdoors, remove hoses and store inside where they are protected from ultraviolet light.
- For sprayer trailers, put blocks under the frame or axle to prevent flat spots on tires during storage.