Which natural weed killer works the best?

By Ned Daniels and Louise Capp

5/6 Smith

27/9/2011

Summary

We investigated “Which natural weed killer works the best”. We used 7 weeds and 4 methods to test our experiment. We took photos over a period of 7 days and then, using word we put the pictures into a graph showing how they reacted. We decided to use non-commercial weed killers because they are environmentally friendly, you know what you are putting into your garden and it costs less than commercial killers. The results showed that white vinegar, salt and detergent works the best on weeds.

Introduction

One day my mum was working in the garden trying to pull out weeds. It was taking a long time and most of them hurt her hands, or didn’t come out. So she decided to use weed killer (Herbicide), but the spray didn’t affect the weeds. So as a result we decided to investigate: “Which natural weed killer works the best”

We researched Weeds and weed killers (herbicides).

What is a weed?

We researched and found out that a weed is a plant that is considered by the owner of the garden as a nuisance and an unwanted plant in human controlled settings, such as gardens and farm fields but also lawns, parks, woods and other areas. More specifically, the word “weed” describes native or non-native plants that grow and reproduce aggressively. Generally, a weed is a plant in an undesired place.

Further explanation of a weed

Weeds generally share similar adaptions that give them advantages and allow them to proliferate (to increase in number or spread rapidly and often excessively) in disturbed environments whose soil or natural vegetative cover has been damaged. Naturally occurring disturbed environments include dunes and other windswept areas with shifting soils, alluvial flood plains, river banks and deltas, and areas that are often burned.

What is a weed killer?

A weed killer, also known as an herbicide is a type of pesticide used to kill unwanted plants.

Some herbicides kill specific targets while leaving the desired crop relatively unharmed. Some of these act by interfering with the growth of the weed and are often synthetic "imitations" of plant hormones. Herbicides used to clear waste ground, industrial sites, railways and railway embankments are non-selective and kill all plant material with which they come into contact. Smaller quantities are used in forestry, pasture systems, and management of areas set aside as wildlife habitat.

Some plants produce natural herbicides, such as the genus Juglans (walnuts), or the tree of heaven. Herbicides are widely used in agriculture and in landscape turf management.

It is also possible to make your own herbicides, for use on your gardens, lawns, flower patches and other areas. You can make these by mixing different liquids (and sometimes solids) together to make combinations to use. The non-commercial herbicides may not work as well as commercial ones but they are cheaper and you can be sure that you are putting in good things for your garden.

What we think will happen.

Louise: I think that the White vinegar, salt and detergent will work the best because vinegar has acetic acid in it and salt stops plants from growing back.

Ned: I think that the White vinegar, salt and detergent method will work the best on the weeds, because the kind of vinegar you buy from the grocery store is usually composed of acetic acid and water, and the salt is said to make the plants not grow back.

We think that the results of our investigation will show that the smaller plants will die first because they won’t be as strong and we also think that the Vinegar, Salt and Detergent will work the best.

Equipment

Jug (at least 1 litre) Spray Bottle 2 bottles of 2 litres of White Vinegar Table Salt Boiling water 500ml Palmolive Dishwashing Detergent

7 sheets of Newspaper 5 different coloured sticks of chalk (we used yellow, blue, green, purple and pink) Camera A large area with a lot of weeds Measuring Cup Funnel 3 large bottles (about 2 litres and plastic so you can see through) 2 Measuring cups, one that holds 1 Cup and one that holds 1\4 cup Teaspoon Water source Kettle Microwave 22 rocks (heavy but not too big)

Methods used to kill the weeds

Boiling Water

Newspaper (covering the weeds).

White Vinegar, Salt and Detergent

Hot- White Vinegar, Salt and Dishwashing Detergent.

Method

List the 5 different killers on a piece of paper that you can come back to. Find an area with a lot of weeds growing through it. (An area that you can draw on, a pavement like this is good).

Select 5 different coloured sticks of chalk. We used green, blue, pink, purple & yellow.

Choose five different groups of weeds (they can be separated but they have to have the same spray applied if they are marked by the same coloured chalk) and draw squares around them with the chalk. Make sure that each square is a different colour according to their groups.

To make the first spray (White Vinegar, Salt and Detergent), Pour 4 cups of White vinegar into a Jug, then pour 1\4 Cup of salt into the same Jug and then 2 tsp of Dishwashing Detergent.

Stir them together until the colour is white (or so it looks like this)

Using the funnel pour your completed spray into one of the three 2 litre Bottles for storage. When you want to use the spray pour it into a spray bottle (as much that fits) and apply 20 squirts of it to the weed. (or enough squirts to equal 25ml) To make the second spray (Hot White Vinegar, Salt and Detergent) repeat the steps given above for the first spray, but just before you apply it to the

weed(s), heat it in a microwave for 2-3 minutes.(apply this straight away as this may go cold)

To make the third spray (Boiling water) Boil 500ml of water in a kettle then pour it into the bottle. (apply this straight away as this will also go cold)

For the fourth method (newspaper), Place 3 sheets of newspaper on either side of the weed and hold it down with rocks so that if there is a heavy wind, the sheets will not blow away. (Make sure that no light can get through as that is why you apply the newspaper) then place one sheet over across the opposite way to the others and hold that down with rocks as well. It should look like this

Leave one weed alone that you will not do anything to, as this will prove that the weeds didn’t just die because of the weather, it was because of the methods. This weed will be called the “control weed”

Write a timetable for when you will check your weeds. (The timetable should have you take photos of each weed once a day, and spray the

weeds once a day. (do this for 6 more days)

Results

Weed 1: Pink 1.

Method: Salt, Vinegar & Detergent.

Info: This is before it was sprayed

Observations: This weed is a bright green colour and most of its leaves are sticking up in the air.

Info: Dead, died after 4 sprays.

Observations: The weed has shrunk and is cracked and dry. The weed appears to be dead,

Info: 1 week later, the final results.

Observations: the weed is completely brown, it is still cracked and dry, and when you touch it, it can easily crumple in your hands.

Weed 2: Pink 2

Method: Salt, Vinegar & Detergent

Info: This is before it was sprayed. Observations: These weeds are all a bright green colour and all of their leaves are sticking up in the air.

Info: Dead, died after 4 days.

Observations: the weed appears to be dead, all its leaves are a yellowish brown, it has fallen Over sideways and they’ve shrunk.

Info: 1 week later, the final results.

Observations: These weeds are a really light brown; they are very thin and can easily come apart.

Weed 3: Blue 1

Method: Hot - Salt, Vinegar & Detergent

Info: This is before it was sprayed.

Observations: This weed is a bright green colour and all of its leaves are sticking up in the air.

Info: Dead, died after 7 days.

Observations: All of the weeds leaves are Brown, it appears to be dead, it has three Stalks standing up but the stalks are brown and are bent, the weed is also dry.

Info: 1 Week later, the final results.

Observations: All of the weeds leaves are brown, it has three leaning stalks, and it is dry and lifeless.

Weed 4: Blue 2

Method: Hot -Salt, Vinegar & Detergent

Info: This is before it was sprayed.

Observations: This weed is a bright green colour and most of its leaves are sticking up in the air.

Info: Dead, Died after 2 days.

Observations: The weed appears to be dead, it is black, it is starting to rip, it is dry and cracked and the weed has fallen over sideways.

Info: 1 Week later, the final results.

Observations: All of the weeds leaves are black, it has blown over to the other side and two of its leaves have ripped off.

Weed 5: Yellow

Boiling Water

Info: This is before it was sprayed.

Observations: This weed is a bright green colour and most of the leaves are sticking up in the air.

Info: The weed didn’t die.

Observations: No observations could be made.

Info: 1 Week later, the final results.

Observations: On some of the edges on the leaves, they are cracked and brown, otherwise there is no change in the weed and it isn’t dead.

Weed 6: Green

Newspaper

Info: This is before it was sprayed.

Observations: These weeds are a bright green colour and all of their leaves are sticking up in the air.

Info: The weed didn’t die.

Observations: No observations could be made.

Info: 1 Week later, the final results.

Observations: The weed is bright green; the weed has not changed at all and does not appear dead.

Weed 7: Purple

Controlled (it is left alone)

Info: This is before it was sprayed.

Observations: This weed is a bright green colour, has two yellow flowers on it and all of its leaves are sticking up in the air.

Info: The weed didn’t die.

Observations: No Observations could be made.

Info: 1 Week later, the final results.

Observations: The weed is bright green, most of its leaves are still sticking up in the air, the weed has not changed at all but the two flowers have closed up.

Discussion

In our investigation we came across a few problems, the rain was the biggest problem in our experiment, as this caused the chalk (that we used to border the weeds\plants) to rub off and go away. The rain also caused the newspaper to go soggy and that made it rip easily, it didn’t rip though, but there was a chance of it happening so the newspaper had to be put down again. Another problem in our experiment was one of our photos got deleted! Luckily we still had a photo of it but it is close up and that was how it was taken so we couldn’t change it.

About an hour after applying the killers, there was already a change in some of the plants; for example, the weeds with pink borders around them had already lost a fair bit of their colour and had started to fall over and slowly start to die, the blue weeds had also lost a bit of their colour and blue weed 2 had already fallen over, but there was no change in the other plants. We think the reason that the vinegar, salt and detergent and the hot- vinegar, salt and detergent worked the best was because the white vinegar is acidic, the salt stops the weed growing back and the detergent helps it stick.

Our hypotheses’ were right! We thought that the salt vinegar and detergent would work best, and it did! We didn’t think the others would work as well as we thought that the newspaper would probably have to be on for a longer time and the boiling water would have to have more of it applied.

Our message to the public is that they try to use non-commercial weed killers, this investigation proved that non-commercial and natural weed killers do work. This investigation also solved our problem and now every time my mum gets weeds out of the pavement she uses our weed killer.

If someone else (or us) were to repeat our investigation we would recommend:

More weeds - It would also be good to use more than one plant for each test to check that the results are accurate. This wasn’t possible for us because we didn’t have enough of the same type of weed in a good space to work on. To start with, we did try to plant the weeds in pots so we could have more of the same type together and also so we could observe them more easily, but this didn’t work because when they were replaced the majority of them died.

To make our investigation more scientific every type of weed should have been tested with each of the weed killers as some of the weeds may be harder to kill than some of the others. The best possible test would have been if we only changed one variable.

More methods to use to kill the weeds (commercial as well) Put the killers on over a longer period of time. (this was not possible for us as we had no spare time) More Photos

Also, if anyone was to investigate further into our experiment these are some of the related investigation we would suggest.

At which temperature does weed killer work best?

In which temperature do weeds die without killers?

Which type of commercial weed killer works the best?

It would also be good to investigate further in to the different parts that make up our first method: salt, vinegar and detergent, to see if all of the three ingredients were necessary, for example, you could test: Detergent alone, Vinegar alone, Salt alone, or mixtures made from two of these ingredients at a time.

You could also make an investigation about the salt to see if it really did stop the weeds from growing back.

We also think that our results will better mankind by killing weeds which makes more room for crops, and will help a garden path look cleaner; it’s also a cheap and fast way to kill plants.

We have also learnt more about weed killers and weeds themselves.

Conclusion

We found out that the Vinegar, salt and detergent and Hot- Vinegar, salt and detergent worked equally the best. The reason why is because the white vinegar is acidic, the salt stops the weed growing back and the detergent helps it stick. We would recommend the Vinegar, Salt and Detergent, rather than the Hot-Vinegar, salt and detergent because even though the results were the same, the second spray was harder to make and you had a risk of burning yourself.

Acknowledgements

Mrs Smith for giving us enough time to complete our science investigation, letting us work on it in class and for giving us the skills and opportunity to do this.

Jane and Stewart Capp for allowing Louise to stay at Ned’s House Marina Daniels for supplying the ingredients for our experiment and some of the catering Nina Daniels, Matt Daniels Maddy Eugster for some of the catering Mrs De Paoli for letting us work on this in class

References/Bibliography

www.wikipedia.org for supplying information about weeds and herbicides. www.tipnut.com for supplying weed killer recipes. http://wiki.answers.com/ for giving helpful information.

Ned Louise

Weeds Tuesday (not sprayed)

Tuesday (after

Wednesday

Thursday Friday Saturday Sunday Monday Tuesday (Result)

Pink 1 White vinegar, salt and detergent

Pink 2 White vinegar, salt and detergent

Blue 1 Hot- Salt, White Vinegar & Detergent Blue 2 Hot- Salt, White Vinegar & Detergent Yellow Boiling Water

Green Newspaper

Purple Controlled