How To Weed A Garden Full Of Weeds

Application
FAQ
Weeds Controlled
Available Sizes
Reviews

Application

How to Apply

Watch how to apply Preen Garden Weed Preventer

When plants are dry, sprinkle this product on soil surface at rate given below for your specific planting situation. Once activated by watering, it forms a weed control barrier in the top layer of soil (1 – 2 inches), preventing weed seeds from germinating. Disturbance to the soil surface after activation may result in erratic weed control.

When to Apply

Apply Preen Garden Weed Preventer during the growing season around established plants and transplants. Preen should not be used on flower seeds. It can be used after flowering plants have germinated and are 2 – 3 inches tall. Preen may also be incorporated into the soil when seeding vegetables or applied after mulching beds. By applying Preen as early as possible, you can eliminate the need for hand‑weeding.

Rain does not wash this product out of the soil. To keep beds weed‑free all season long, reapply Preen weed preventer every 9 – 12 weeks.

Applying Around Established and Transplanted Plants

For flowers, roses, herbs, ground covers, ornamental grasses, shrubs, trees, and listed vegetables at least 2 – 3 inches tall, sprinkle Preen Garden Weed Preventer evenly over the entire soil surface, at the rate of 1 oz per 10 sq ft, being sure to keep granules away from plant roots and foliage. Immediately water. If watering-in is not convenient, lightly rake into soil surface. Always wash or brush off stray weed preventer granules from plant foliage to avoid damage or discoloration.

Applying with Mulch

For best weed control, we recommend applying Preen Garden Weed Preventer after spreading mulch on your flower and shrub beds. Sprinkle Preen on top of the mulch being sure to keep granules away from plant foliage. Immediately water this product into the mulch. If watering-in is not convenient, lightly rake into top layer of mulch. Always wash or brush off stray granules from plant foliage to avoid damage or discoloration.

This is not the product label. Always read and follow directions on the product label. Use only as directed.

FAQ

Coupons
General Product Questions
Proper Use
Staining
Human & Pet Safety
Product Misapplication
Use around Seeds and Young Plants
Use with Mulch
Where to Apply Preen
Storage and Disposal

Coupons

Do you offer coupons, rebates, etc?: Very often our retailers or mass merchants offer their own special sale price, coupons or rebates. Local flyer, newspaper inserts, and media advertising can alert you to these offers.

General Product Questions

What is the active ingredient in Preen^® Garden Weed Preventer?

1.47% Trifluralin (Treflan).

What are the other ingredients in Preen^® Garden Weed Preventer?

Preen^® Garden Weed Preventer contains a carrier agent such as corn cob and biodac (recycled newsprint) in addition to the active ingredient.

What weed seeds does Preen^® Garden Weed Preventer prevent from germinating?

See our list of weeds controlled on the product label.

How long does Preen^® Garden Weed Preventer prevent weed seeds from germinating?

Up to 12 weeks per application. Reapplication may be necessary sooner during periods of heavy rain or excessive heat and humidity; or if you have porous, sandy type soil.

How long does Preen^® Garden Weed Preventer stay in the soil?

Approximately 8 – 12 weeks per application. The rate at which Preen^® Garden Weed Preventer biodegrades will depend on temperature, soil type, rain/moisture, sunlight and amount applied.

What weeds does Preen^® Garden Weed Preventer kill?

None. Preen ^® Garden Weed Preventer helps to prevent germination of seeds from the list of weeds shown on the label for up to 12 weeks per application. It does not kill or inhibit existing weeds in any way.

How much water must I apply to activate Preen ^® Garden Weed Preventer?

After application, you only need to apply enough water to thoroughly wet the surface of the soil. The granules will not dissolve. They will disintegrate over a period of weeks.

What are the particles on the soil surface after I watered Preen^® Garden Weed Preventer?

Once Preen ^® Garden Weed Preventer is watered in, the carrier, such as corn cob or biodac will remain on the surface and biodegrade over time.

How does Preen^® Garden Weed Preventer work?

Preen^® Garden Weed Preventer works to create a barrier that inhibits weed seed growth. The barrier can last up to 12 weeks.

Will rain wash Preen^® Garden Weed Preventer away?

No, but heavy rain may shorten its effective period.

Why is the Preen^® Garden Weed Preventer container not completely full?

Our product container is packaged/sold by weight, not by volume. If you weigh the container you will find that the weight is as stated or slightly higher.

Do you have a guarantee on your products?

Preen^® Guarantee: To the extent consistent with applicable law, Lebanon Seaboard Corporation guarantees you will be satisfied with the performance of Preen^® products when used as directed, or your money back. If not satisfied, describe the nature of your problem, and send with proof of purchase to:

Lebanon Seaboard Corporation
1600 East Cumberland St.
Lebanon, PA 17042

Proper Use

How close can I apply Preen^® Garden Weed Preventer to a non-recommended plant?: Apply at least 12″ outside the drip-line of a non-recommended plant.
What does "established plant" mean on the Preen^® Garden Weed Preventer label?: This term refers to plants at least 3" in height. If recently transplanted, do not apply Preen^® Garden Weed Preventer until plants have been watered once or twice to make sure the soil is well and uniformly settled around the plants. An established ground cover is one that has spread and filled in to your satisfaction.
What does "non-bearing" fruit and nut trees mean?: This term refers to established fruit and nut trees that have not matured to the point of producing a harvest. Preen^® Garden Weed Preventer can be applied around the label listed non-bearing fruit and nut trees until they begin bearing fruit or nuts; otherwise, it cannot be applied.
When do I apply Preen^® Garden Weed Preventer?: Apply Preen^® Garden Weed Preventer at the first sign of active growth or germination on your property; this includes bulb emersion or foliage growth.
Is there a benefit to applying Preen^® Garden Weed Preventer in the fall?: Raking leaves and garden debris or other fall activities that disturb garden soil can expose weed seeds. The months of September and October are perfect months for a fall application as many weeds actively grow in these months.
Do I have to weed first before applying Preen^® Garden Weed Preventer?: Preen^® Garden Weed Preventer does not kill existing weeds. The ideal application is to hand-pull or spray existing weeds before applying Preen. If there is no opportunity to remove weeds first, an initial application can be utilized to prevent further weeds until you have an opportunity to clear the garden and landscape beds. Note that Preen^® Garden Weed Preventer will not control weeds that are just tilled under.
When do I reapply Preen^® Garden Weed Preventer?: Reapply every 8 – 12 weeks in the growing season and more often during periods of heavy rain or prolonged periods of high heat and humidity.
Can Preen^® Garden Weed Preventer be applied when plant foliage is wet?: No; plant injury could result if granules fall on wet leaves.
Does Preen^® Garden Weed Preventer need to be watered-in?: Yes; rain or water must immediately follow application to activate the product.
What happens if rain or water does not immediately occur after application?: Preen^® Garden Weed Preventer will not start to work until rain or watering occurs. If watering is not an option, time your application with rain, or lightly rake Preen^® Garden Weed Preventer into the soil to protect it from sunlight until rain occurs.
How much Preen^® Garden Weed Preventer should I apply?: For label recommended flowers, trees, shrubs, and groundcovers, sprinkle granules lightly and evenly over the soil. Use a process similar to salting or peppering food, approximately 1 oz (4-5 tsp) per each 10 sq. ft. For label recommended vegetables, apply 1 pound per 640 sq. ft. For heavy clay or medium loam (roughly equal parts sand, silt and clay) soils, apply 1 pound per 960 sq. ft.; and apply 1 lb. per 1,280 sq. ft. for light sandy soils.
Can Preen^® Garden Weed Preventer be applied on plant foliage or exposed plant roots?: No; plant injury could result.
What do I do if Preen^® Garden Weed Preventer accidentally got on plant foliage during application?: You can dry-brush or thoroughly and immediately rinse off the granules from plant foliage with a garden hose.
How do you use Preen^® Garden Weed Preventer with flowers, trees, and shrubs?: Remove existing weeds and weed roots. Then apply Preen ^® Garden Weed Preventer to soil around plants and rake or water in thoroughly.
How do you use Preen^® Garden Weed Preventer with groundcovers?: Ensure your groundcovers are fully established and are listed on the product label. Remove existing weeds and weed roots. Then apply Preen^® Garden Weed Preventer around the dry foliage and water immediately.
Why can't I apply Preen^® Garden Weed Preventer to muck (constantly wet) soil or soils containing more than 10% organic matter?: These types of soils will neutralize the active ingredient in Preen^® Garden Weed Preventer.
When do I apply Preen^® Garden Weed Preventer with bulbs?: Preen^® Garden Weed Preventer may be applied in fall and again in spring over an area where any label listed bulbs are buried. If foliage has come through the soil, avoid contact with plant leaves.
Does Preen^® Garden Weed Preventer control weeds that have been tilled under?: No; weeds that are not completely removed will emerge again.
Do I apply Preen^® Garden Weed Preventer by hand?: No; apply with either the refillable shaker canister, the scoop included in some larger size containers, or your own applicator. You may also purchase Preen Garden Weed Preventer in a power spreader canister if available in your area.
Can I mix Preen^® Garden Weed Preventer with water before application?: No; mixing with water dilutes the active ingredient and renders the product ineffective.
How long after an application of Preen^® Garden Weed Preventer should I wait before planting non label-recommended plants?: Wait 12 weeks from when the product was applied.

Staining

Can Preen^® Garden Weed Preventer stain?

Yes; Preen^® Garden Weed Preventer can stain porous surfaces such as concrete, rocks, bricks, landscape blocks, shoes, leather, linoleum, vinyl, and carpet.

How do I prevent possible staining?

Never apply Preen^® Garden Weed Preventer when any surrounding porous surface is wet. Dry brush stray granules off any non-target surface before watering the area to activate the product. Store Preen^® Garden Weed Preventer packages in a garage or shed on top of cardboard or newspaper. Never place container on a linoleum, vinyl, tile or carpeted floor.

How can I get rid of a Preen^® Garden Weed Preventer stain?

Try Goo Gone or another citrus-based cleaning product to lessen the appearance of or remove a stain. Always test a small area first to ensure the product won't cause additional staining.

For porous surfaces: Use equal parts soapy water and bleach, or a paste of baking soda and water, or ultraviolet light/sunlight, or a citrus-based cleaner, or 409 carpet foaming spray cleaner. Always follow manufacturer's directions.

For non-porous, uncoated surfaces: Use acetone or an acetone based nail polish remover.

Human & Pet Safety

Where can I find emergency medical information for Preen^® Garden Weed Preventer?: Immediately call ProPharma toll-free at (888) 208-1368 and/or 911.
When can people and pets enter an area that was treated with Preen^® Garden Weed Preventer?: They may enter the treated area after it is thoroughly dry from the first rain or watering.
Can I walk on a Preen^® Garden Weed Preventer treated area?: Limit walking on a treated area, as soil disturbance will result in erratic weed prevention.

Product Misapplication

What can I do if I applied Preen^® Garden Weed Preventer to my lawn, flower, or grass seeds, a non-recommended plant, etc.?

The active ingredient should be neutralized using activated charcoal granules (also called activated carbon). Activated Charcoal can be found at garden centers, pool supply stores, pet stores, or in the aqarium supply section of stores. Call the store first to confirm availability. Charcoal bricks used in a grill will not work.

Sprinkle activated charcoal granules onto the soil surface at a rate of one pound per 100 square feet.
Gently rake the activated charcoal into surface of soil.
Thoroughly water the activated charcoal treated area.
Repeat the watering schedule for three days.
Cease watering. After two days, the active ingredient in the product will be neutralized

Preen^® Garden Weed Preventer was over-applied in my garden. How can I save my plants from injury?

If rain or watering did not occur: Physically remove Preen^® Garden Weed Preventer granules.

If rain or watering did occur, or if you were unable to physically remove the granules, neutralize the product following these steps:

The active ingredient should be neutralized using activated charcoal granules (also called activated carbon). Activated Charcoal can be found at garden centers, pool supply stores, pet stores, or in the aquarium supply section of stores. Call the store first to confirm availability. Charcoal bricks used in a grill will not work.

Sprinkle activated charcoal granules onto the soil surface at a rate of one pound per 100 square feet.
Gently rake the activated charcoal into surface of soil.
Thoroughly water the activated charcoal treated area.
Repeat the watering schedule for three days.
Cease watering. After two days, the active ingredient in the product will be neutralized.

Use Around Seeds and Young Plants

Will flower seeds germinate with Preen^® Garden Weed Preventer?: Flower seeds will not germinate while Preen^® Garden Weed Preventer is active (about 9 -12 weeks per application).
How long after an application of Preen^® Garden Weed Preventer should I wait before planting label-listed annual flower transplants?: If transplanting into a Preen® treated area within 9 - 12 weeks of application, clear an area around the transplant hole to ensure no treated soil is introduced into the planting hole. After placing plant, backfill the hole with untreated soil or a planting mix. Preen granules should not come in contact with plant roots. If possible, it is recommended to plant first, then apply Preen® Garden Weed Preventer.
I have planted my annual flower transplants. How long do I need to wait to apply Preen^® Garden Weed Preventer?: Preen^® Garden Weed Preventer may be applied around any label listed transplant after the plants have been watered once or twice to make sure the soil is uniformly settled around the plants. Avoid getting granules on plant leaves. Water area immediately after application.
How do I apply Preen^® Garden Weed Preventer with vegetables?: Check the vegetable section on the label to make sure your plant varieties are approved and have been watered well once or twice to ensure soil has uniformly settled around the plants. Then, apply Preen Garden Weed Preventer around plants and between rows and water the area thoroughly. Avoid getting granules directly on the plants.

Use with Mulch

Should Preen^® Garden Weed Preventer be applied before the mulch is applied (directly on the soil) or on top of mulch?: For best weed prevention, we recommend Preen^® Garden Weed Preventer be applied to the weed free soil, watered lightly, and then covered with 2 - 3 inches of mulch. Because weed seeds can be present or introduced into the mulch, another application of Preen^® should be made over the mulch and thoroughly watered. Repeat the Preen application over the mulch every 2 - 3 months during your growing season.

Where to Apply Preen

Can Preen^® Garden Weed Preventer be applied to corn?: No; Preen^® Garden Weed Preventer is not labeled for use on corn.
Can Preen^® Garden Weed Preventer be applied to strawberries?: No; Preen^® Garden Weed Preventer is not labeled for use on strawberries.
Can I use Preen^® Garden Weed Preventer on my lawn or with grass seed or sod?: No; turf injury could result. Preen^® Garden Weed Preventer is not labeled for use on lawns.
Can I use Preen^® Garden Weed Preventer in or near a pond, lake, or other type of waterway?: No; Preen^® Garden Weed Preventer is harmful to aquatic life. Do not use if there might be any chance of runoff into the water.
Can I use Preen^® Garden Weed Preventer around, under, or near a swimming pool, sandbox, playground type area, or under bird feeders?: No.
Can I use Preen^® Garden Weed Preventer in or near a greenhouse or any type of enclosed area?: No; staining and/or volitization could occur causing plant injury.
Can Preen^® Garden Weed Preventer be used in potted plants or planter boxes?: No; plant injury could result.
Can I use Preen^® Garden Weed Preventer where chickens, horses or other animals graze?: No.
Can I use Preen^® Garden Weed Preventer on a garden slope or hillside?: Yes, if a waterway is not at the bottom of the slope or hillside.
Can I use Preen^® Garden Weed Preventer on decorative stones or pebbles?: Preen^® Garden Weed Preventer can stain porous materials such as stone or brick. Before treating your entire area, do an application to a small area to test for staining, which would appear within a few days. Always apply when stones are dry and water thoroughly immediately after application.
What plants are recommended with Preen^® Garden Weed Preventer?: See the list of compatible plants on the product label , or consult out our plant compatibility tool.
Can I use Preen^® Garden Weed Preventer with a plant that is not listed on the product label?: Preen can be safely used with all plants listed on the product label. If your plant is not listed this indicates it was not included in the product research and the safety of use on non listed species is inconclusive. Users who wish to use Preen on non-listed plant species should start with a trial application at the recommended rate to a small number of plants. Treated areas should be observed for 30 to 60 days of normal growing conditions to determine if applications are non-injurious. The user assumes responsibility for any plant damage or other liability resulting from the use of Preen on plant species not recommend on this label.

Storage and Disposal

Does Preen^® Garden Weed Preventer expire?: No. Preen^® Garden Weed Preventer has an indefinite shelf-life as long as it is sheltered from moisture and sunlight.
Can Preen^® Garden Weed Preventer be stored for next year?: Yes; store in a dry place away from sunlight and moisture, atop a piece of cardboard or newspaper. Never store directly on a linoleum, vinyl, tile, or carpeted surface, as staining may occur.
How do I dispose of Preen^® Garden Weed Preventer or its empty container?: Disposal requirements differ from place to place. Call your local municipality to inquire on proper product disposal and/or package recycling, or call 1-800-CLEANUP. If not recyclable in your area and container is empty, place empty container in trash.

Weeds Controlled

annual bluegrass ( Poa annua )
barnyardgrass ( Echinochloa crus-galli )
brome ( Bromus spp. )
carelessweed
carpetweed ( Mollugo verticillata )
cheat grass ( Bromus tectorum )
chickweed ( Stellaria media )
Crabgrass ( Digitaria sanguinalis )
fall panicum ( Panicum dichotomiflorum )
Florida pusley ( Richardia scabra )
goosefoot
goosegrass ( Eleusine indica )
guineagrass ( Urochloa maxima )
hare barley ( Hordeum murinum ssp. leporinum )
henbit ( Lamium amplexicaule )
Johnsongrass ( Sorghum halepense )
junglerice ( Echinochloa colona )
kochia ( Kochia scoparia )
lambsquarters ( Chenopodium album )
lovegrass ( Eragrostis curvula )
prostrate knotweed ( Polygonum aviculare )
puncturevine ( Tribulus terrestris )
purslane ( Portulaca oleracea )
rattail fescue ( Vulpia myuros )
Russian thistle ( Salsola iberica )
sandbur ( Cenchrus spp. )
signalgrass ( Brachiaria spp. )
southwestern cupgrass ( Eriochloa acuminata )
sprangletop ( Leptochloa spp. )
stinging nettle ( Urtica dioica )
stinkgrass ( Eragrostis cilianensis )
Texas panicum ( Urochloa texana )
wild cane ( Sorghum bicolor )
wild oat ( Avena fatua )
wildcane
witchgrass ( Panicum capillare )
woolly cupgrass ( Eriochloa villosa )
yellow foxtail ( Setaria glauca )

Available Sizes

Preen Garden Weed Preventer Bottle (5.625 lbs)

Covers 900 sq ft

2463795
Preen Garden Weed Preventer Bag (13 lbs)

Covers 2,080 sq ft

2463798
Preen Garden Weed Preventer Drum (16 lbs)

Covers 2,560 sq ft

2463800
Preen Garden Weed Preventer Bag (31.3 lbs)

Covers 5,000 sq ft

2463802

Reviews

To review a particular product within this family please choose from one of the available sizes below, or you may continue to write a review for Preen Garden Weed Preventer without selecting a size.

Rated 5 out of 5 by Drew from Worth the money, so far! I have used this product for the 1st time this year after I redid my landscaping and this product seems to be doing exactly what its suppose to do, so far!

Date published: 2021-06-28

Rated 1 out of 5 by Jen W from Not impressed I used this 2 weeks ago and followed the instructions. Weeds have already come back.,

Date published: 2021-06-13

Rated 1 out of 5 by Tony E from Absolutely worthless I tilled my veggie garden mid March then applied Preen heavily, raked and watered in. Tilled again mid April, applied heavily again and watered in. Planted May 1. Now weeds starting everywhere. Should one should apply it so thickly that it acts as a mulch? See pic and scroll in

Date published: 2021-05-21

Rated 1 out of 5 by Lita from Great job except this year! I have used Preen Weed Preventer and had success for the past 10 to 15 years. This year, it did not work at all. I applied it the same as I have in other years just before a rainfall, with the scoop, etc. I have never weeded more than this year! The same weeds it has prevented in the past are taking over my landscaping. I have talked to a few people who use it, including family members, and they seemed to have the same situation as I am experiencing. What happened this year? I use 4 of the 16# size. It was unfortunately a big waste of money and time this year. Disappointed.

Date published: 2020-07-07

Rated 1 out of 5 by lks18 from Huge disappointment bought the black mulch with the weed prevention and didn't work at all. Within a few days I had more weeks than normal. Huge disappointment

Date published: 2020-05-27

Rated 1 out of 5 by Nate D from Waste of money. Doesn't work. We bought two huge buckets of this stuff every year for the past 3 years from Costco. It has never ever worked. Don't buy. Doesn't do anything. We pulled all existing weeds, put Preen down and a month later we have hundreds of weeds (dandelions, vines, thistles). Stuff is garbage. Waste of money. Will never buy again.

Date published: 2020-05-10

Rated 1 out of 5 by Oman64 from Didnt work at all I bought 5 large bags of this and applied it to my lawn generously a week and a half ago. Dandelions look like they did before i applied it. I followed all the instructions and does not work. I even saw the granules sticking to the weeds as they should. 120 bucks down the drain.

Date published: 2020-04-03

Rated 5 out of 5 by Theressa from Used Preen for 20+Yrs. I would not have used Preen over 20 years if I wasn't happy with it. Theressa

Date published: 2020-03-03

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