6 Ways to Kill Weeds, Naturally or With Chemicals
6 Ways to Get Rid of Weeds
Weeds are unsightly and spoil neatly tended flower beds and borders, yards and driveways. Fortunately there are lots of ways to deal with them, either with chemicals or in a natural, environmentally friendly way, by mechanical means or with household chemical chemicals.
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What is a Weed?
"A weed is an undesired plant, growing in the wrong place".
Yep, that's basically it! There aren't special plants called "weeds" that evolved just to spoil our gardens! Weed isn't a botanical term like annual or perennial or evergreen that describes a particular type of plant. The concept of a weed is subjective and generally it applies to wild flowers, often with ugly foliage or insignificant flowers that spread happily through our flower beds and on our driveways. They could also be cultivated flowers that we have sown and which have now self seeded in abundance or propagated by other means and spread everywhere we don't want them to.
"A weed is an undesired plant, growing in the wrong place"
How Do I Kill Weeds in my Garden?
- Use a hoe
- Smother them with bark mulch or chipped branches
- Burn them with household chemicals
- Burn them with a blow torch
- Kill them with a systemic weedkiller
- Smother them with plastic or carpet
Method 1 - Use a Hoe
A hoe is excellent for slicing through the stems of weeds. However, if weed growth is extensive on a gravel driveway or in flower beds, the hoed vegetation can be unsightly and may need to be raked up. It's best to hoe in very dry weather so that vegetation dries up rapidly. If you hoe in wet weather and leave weeds lying on the surface of soil, they may take root again if the plants and roots are intact.
A hoe should be kept razor sharp. You can sharpen the blade with a sharpening stone or angle grinder. See link: Sharpening a spade with an angle grinder
Method 2 - Use Bark Mulch or Chipped Branches
Mulch is material applied to the surface of soil which helps to suppress weeds and retain moisture. This could be grass clippings from the lawn, bark mulch etc. You can buy bark mulch or make your own chippings from branches using an electric chipper. (See link http://eugbug.hubpages.com/video/Recycle-Garden-Waste-With-a-Shredder ) These normally cost less than $200.
Mulch can be used around the trunks of trees to prevent grass growth and the need for string trimming. It can also be applied to flower beds to suppress weed growth. Bark mulch or chippings can be used to create natural pathways in the garden also.
Method 3 - Burn Them With Household Chemicals
Bleach, vinegar and salt will all burn the top growth of weeds and stunt their growth. This is quite effective at killing young seedlings. Established weeds with lots of top growth will grow back, but if they are continually deprived of their leaves, any energy stored in the root will eventually run out and without leaves to produce more energy, they will die. However you need to be persistent.
You can experiment with concentrations but initially try mixing vinegar with equal quantities of water. Mix 1 part bleach with 10 parts water. If using salt, mix 1 part salt with 10 parts water and add about 2 tablespoon of washing up liquid per gallon to make the solution stick to the leaves.
Make sure you spray in dry weather and if using bleach, protect your eyes with goggles.
Method 4 - Use a Blow Torch
A propane / butane blowtorch such as the ones used for torching bituminous felt onto roofs is ideal for burning the top growth of weeds. You don't actually have to incinerate the weeds, just scorch them and they will die after a couple of days. As is the case with using bleach or salt, the results are variable and weeds may grow back. Deep rooted rooted perennial weeds such as dandelions will definitely re-grow. Burning is effective against young seedlings.
Be careful in dry weather to avoid dry grass and conifers. You don't want to be responsible for starting a bush fire!
Method 5 - Use a Systemic Herbicide
Glyphosate is a broad spectrum herbicide which is very effective against annual and perennial weed and grasses. Systemic means that the weed killer is absorbed through the leaves and over a period of 1 to two weeks works its way down down through the plant into the roots.
Glyphosate is well known under the Monsanto brand name "Roundup". However since the patent expired in 2000, it is available from other manufacturers at lower cost.
The herbicide is of low toxicity ( at least that is what current evidence suggests). It is supplied in varying strength formulations and the 360 g/l product is diluted at a rate of 2.5 % concentrate by volume with water. This is equivalent to 25 ml per liter (litre) or 3.2 U.S. fluid ounces per U.S. gallon. Consult the instructions supplied with your product for recommended dilution rates.
A knapsack sprayer can be used or a smaller 1 gallon or 5 liter sprayer. You can also use spray bottles such as the ones window or shower cleaner comes in, for spot treating weeds. Make sure they are washed out first and write on the bottle what it contains, so that weedkiller doesn't end up on your windows or in your shower! You can buy ready made instant spray bottles which saves you having to mix concentrate with water, but these are really uneconomical as you are just paying for water.
What is the Best Time of the Year and Suitable Weather Conditions to Use Weed Killer?
Don't spray on windy days to avoid drift onto lawns or flowers and resulting "collateral" damage! Keep the spray head close to the ground when spraying edges of lawns and around flower beds or shrubs. This makes the spray circle smaller so that there is less chance of getting weed killer on your prized plants. 6 hours is required for spray to dry, and ideally 24 hours for absorption to occur before rain. Anecdotally it's supposed to be a good idea to add a few squirts of washing up liquid to the mix which helps it to stick better if there's light rain. It's best to spray weeds when they have lots of top growth and actively growing to maximize the amount of herbicide absorbed. Don't spray in very dry weather or when there is a drought as plants will have reduced their metabolism and weed killer won't spread through the plant.
Spray weeds before they get a change to develop flowers and re-scatter seed. Weed killer won't kill un-germinated weed seeds on the ground and you will end up having to re-treat once they germinate.
Method 6 - Use Plastic Sheeting, Old Blankets or Carpet
Sheets of plastic can be used to suppress weeds. You can use black plastic refuse sacks, buy a roll of plastic or even use old carpet, blankets, newspapers or cardboard. This works by blocking out the light and if plastic is used, it dries out the ground. Black plastic may not be completely opaque (especially bin bags which are quite thin) so check this out first. Killing weeds this way is a slow process and not recommended for impatient gardeners! It can take weeks to several months for weeds to die, especially in the case of creeping weeds when the roots may be located outside the plastic.
1. Common and Scientific Names of Weeds - University of California Agriculture & Natural Resources
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
Questions & Answers
How do I get rid of invasive horsetail?
Horsetail is deep-rooted perennial weed that will spread to cover an area if it's not dealt with.
You can try and fork out roots and shoots growing near the surface, but the weed can re-sprout from small pieces left behind. Glyphosate (Roundup or other brands) can be used as a chemical herbicide, and is best applied in late summer. It's a good idea to damage the shoots by bruising with a rake to help absorption.Helpful 1
Can I use just salt and water to get rid of weeds? And if so, how should it be mixed, and when should I apply it?
Yes. You can mix salt and water; three parts water to 1 part salt. You can also add vinegar for a better effect. The best time to apply is when there's no imminent rain to wash it off, and the weather is very dry as weeds will be already under stress due to lack of water.
Salty water is effective against young seedlings, but it'll need to be repeatedly applied to more mature plants with more developed root systems. It's not effective against deep-rooted perennials such as dandelions. Salt can damage your soil, killing microorganisms and worms and binding to minerals in the soil, so you need to take this into account if you're going to be growing flowers and vegetables in the future. On paths and driveways, this is unlikely to be a concern.Helpful 5
© 2014 Eugene Brennan