Garlic Mustard Invasion

Experiment 1: Does Garlic Mustard lower soil quality for native plants?

Materials Needed (All items are contained in Kit unless noted):

36 Rocket Pots
2 racks for pots
Filter paper
Labeling tape
Sharpie marker
Bamboo stick
Sterilized background potting soil
Elymus hysterix (eastern bottlebrush grass) seeds
500 mL beaker
Small plastic cups
Gallon Ziploc bags
Microwave (provided by you)
Control field soil from un-invaded forest Local field soil collected from underneath garlic mustard (collected by you and labeled GM)
Local field soil collected away from garlic mustard (collected by you and labeled AWAY)

Step 1: Create sterilized soils by microwaving.

Take half of the soil from each of the samples and place it in a new Ziploc bag labeled as GM-sterile, Away-sterile, and Control-sterile depending on which sample it is.

Do not zip the “sterile” bags closed. Microwave “sterile” bags one at a time on high for 4 minutes each to kill any fungi existing in the soil.

Set the bags aside or in a refrigerator to cool. (CAUTION – BAGS WILL BE HOT)

Step 2: Label all of the pots according to their treatment. There will be six treatments total, (a microwaved or not microwaved version of three soil types: 2 X 3 = 6). We will make six pots for each treatment, giving a total of 36 pots.

Label the first six pots: GM 1, GM 2, GM 3, GM 4, GM 5, and GM 6.

Label the next 6 pots: GM-Sterile 1, GM-Sterile 2, GM-Sterile 3, GM-Sterile 4, GM 5, and GM-Sterile 6;

Label the next 6 pots: Away 1, Away 2, Away 3, Away 4, Away 5 and Away 6

Label the next 6 pots: Away-Sterile 1, Away-Sterile 2, Away-Sterile 3, Away-Sterile 4, Away-Sterile 5 and Away-Sterile 6

Label the next 6 pots: Control 1, Control 2, Control 3, Control 4, Control 5, Control 6

Label the last 6 pots: Control-Sterile 1, Control-Sterile 2, Control-Sterile 3, Control-Sterile 4, Control-Sterile 5, Control-Sterile 6

Step 3: Filling the pots

Make a filter paper cone for the bottom of each pot to prevent the soil from running out the bottom. To do this, take a circle of filter paper and fold it in half, and then in half again to get a wedge four layers thick. Pull out one layer to make a little cone. Then place this cone into the pot and use the bamboo stick to gently push it to the bottom of the pot, so that the tip of the cone sticks out of the hole in the bottom of the pot. Don’t push too hard or you will poke a hole in the filter paper. One sample cone has been included in your kit.
Using the plastic beaker, add 500 mL of the sterilized potting soil (provided in the big trash bag) to each pot. Do this in an area that can get a little messy and will be easy to clean up.
This is the crucial step, so be extra careful here and use a new cup for each soil type to avoid contamination.
1. Make sure the microwaved soils have cooled.
2. Use the small plastic cups provided to add 60 mL of GM soil to each of the six pots labeled GM. (The cup holds exactly 60 mL if you make sure to level the soil with the rim of the cup). Throw cup away.
3. Get a new cup, and then add one scoop of the GM-sterilized potting soil to each GM-Sterile pot. This will help prevent contamination from one pot to the next. Throw cup away.
4. Repeat step C for: Away, Away-Sterile, Control and Control-Sterile until all 36 pots are filled.

Step 4. Place the pots in the racks in a randomized order to make sure the plants from each treatment aren’t all grouped together. Click here for a randomized sample diagram.

Step 5. Growing the plants

Water each pot until the soil is moistened all the way through. Add as much water as you can to each pot before it overflows, and then wait for the water to trickle through. Repeat this process a few times until the soil seems saturated and the filter paper at the bottom of each pot is wet.

Add four Elymus hysterix (eastern bottlebrush grass ) seeds to each pot. The seeds do not need to be buried.

Add a little more water to each pot, being careful not to float the seeds out of the pot.

Set the racks in an area where the plants will get some light and it will not get too cold.

Check on the pots daily until the seeds have germinated. Add water as necessary to keep the soil moist. Once a seed has germinated in a pot, remove any other seedlings that emerge in that same pot. (We added four seeds per pot to make sure we got at least one to germinate, but we only want to grow one plant per pot).

Water pots as needed over the next 6 weeks.