How to measure the growth rate of plants

Video: How to Measure Growth Rate of Plants

Content

Steps
Method 1 of 4: Measure the height of the plant
Method 2 of 4: Estimate leaf sizes
Method 3 of 4: Weigh a live plant
Method 4 of 4: Weigh the dried plant
Tips
Warnings
What do you need
Additional articles

Measuring the growth rate of plants is an extremely simple procedure that requires minimal effort and time. In this case, several measurements should be taken over several days or weeks. If you want to determine how much a plant has changed, measure its height and leaf size.If your goal is to find out the amount of water absorbed by a plant, try weighing this plant. The most accurate way to determine the growth rate of a plant is to weigh it dry, but this will kill the plant. This method can be used if you have many plants of the same type and you need to measure the growth rate very accurately.

Steps

Method 1 of 4: Measure the height of the plant

1 Place the end of the ruler at the base of the plant. Smaller plants can be measured with a ruler, while taller plants will need a tape measure or folding rule. Make sure that the zero mark of the ruler is at the bottom.
- If you are measuring a potted plant, the zero mark should be at soil level.
2 Write down the height of the plant. Measure the plant from its base to its highest point. Record your result and indicate the date of measurement. Repeat measurements every 2-3 days.
3 Calculate the average growth rate using the formula. Based on the results of measurements, you can find the average growth rate for one day: to do this, divide the change in height by the number of days during which it occurred.
- The formula for the growth rate is as follows: ${ displaystyle { frac {(S2-S1)} {T}}}$ where S1 is the starting altitude, S2 is the ending altitude, T is the number of days between two measurements.
- As a result, you will get an average value. The growth rate of plants is not constant; it changes quite a lot from day to day. It is currently impossible to predict the growth rate of plants even in the coming days without the use of sophisticated laboratory equipment.

Method 2 of 4: Estimate leaf sizes

1 Build a table. The number of rows in the table must match the number of dimensions. Label the columns as “number of leaves”, “average length” and “average width”. In this method, the leaves should be measured every 2-3 days.
2 Count the number of leaves on the plant. Be careful not to skip leaves or count the same leaf twice. Consider newly emerging leaves and shoots that have not yet blossomed. Write down the number of leaves in the table.
3 Measure the length and width of the leaves. Pick 4 or 5 random leaves. Use a ruler to measure length along the sheet, from base to tip. Then add all the measured values and divide by the number of measurements. For example, if you measured five leaves, divide the sum of their lengths by 5. This gives you the average leaf length for a given date. Record the result in the table.
- Similarly, measure the width of the leaves, find the average, and write it down in the table.
- Try to be as precise as possible. Measure the length and width of the leaves to the nearest centimeters and even millimeters.
4 Find the area of the leaves using graph paper. Place the sheet gently against the graph paper so as not to damage it. Circle the sheet with a pencil. On the paper, there are squares with an area of one square millimeter each. Count the number of squares in one sheet. Do the same with the other selected leaves.
5 Repeat measurements every 2-3 days. The leaves grow quite quickly. Check the size of the leaves every few days to find out how much they have grown. You can use one of the varieties of the growth rate formula to analyze the results.
- From the measurements, the growth rate of the leaves can be calculated. Using the Growth Rate Formula, you can determine how much leaves will grow in one day. The formula looks like this: ${ displaystyle { frac {(L2-L1)} {T}}}$ , where L1 is the initial measurement, L2 is the final measurement, T is the number of days between two measurements.
- The formula for leaf size looks the same as the formula for plant height. In the case of leaves, the area should be substituted into the formula.The rate of increase in leaf area is calculated using the following formula: ${ displaystyle { frac {(S2-S1)} {T}}}$ , where S1 is the starting area, S2 is the ending area, T is the number of days between two measurements.
6 Visualize the growth of the leaves. After observing the leaves for several weeks, you can visualize their growth. Take a piece of paper or cardboard and draw a circle on its edge, the area of which roughly corresponds to the initial area of the leaves. Then draw a few more (for example, six) circles around the first, so that their area corresponds to the results of subsequent measurements. As a result, you will end up with a set of concentric circles. Place a number next to each circle. The first circle will be the smallest and the sixth the largest.
- This image can be used to measure leaves more easily and quickly. Place the sheet against the edge of the paper so that its base coincides with the smallest circle and mark the number of the circle, beyond which the sheet does not go.

Method 3 of 4: Weigh a live plant

1 Remove the plant from the soil. If the plant is in a pot, gently scoop up the soil around the edges with a scoop. If the plant is in the ground, dig a wide enough circle around it. Be careful not to touch the roots. Gently lift the plant up and shake off any large clods of soil from the roots. Don't pull the plant too hard or jerk it.
2 Flush the soil off the roots. Run the water under a gentle pressure and rinse the roots. Use your fingers to gently remove any clods of dirt. Then blot the roots with a paper towel.
3 Place the plant on the scale. Do not over tighten, otherwise the plant may lose the moisture it needs. Put it on the scale. Use a scale that can determine your weight to the nearest milligram. Record your measurements.
4 Place the plant back on the ground. Dip the roots into the remaining hole and sprinkle them with fresh soil. If you have taken the plant from a pot, add some soil mixture to the bottom of the pot before lowering the roots into it. Then sprinkle the roots with fresh soil mixture so that the ground level is 2-3 centimeters below the top of the pot. After that, water the plant to replace the water lost.
5 Wait a month before re-weighing. Avoid weighing the plant too often, as this can harm it, stunt growth or even kill it. If you handle the plant carefully and do not touch the roots, it can be removed from the ground and weighed several times, but be extremely careful.
6 Calculate the growth rate of the plant. After the second measurement, calculate the average growth rate using the following formula: ${ displaystyle { frac {(W2-W1)} {T}}}$ , where W1 is the initial weight, W2 is the final weight, T is the number of days between weighings.

Method 4 of 4: Weigh the dried plant

1 Choose one of the plants you are interested in. This method will kill the plant, so it is suitable if you have several of the same plants. Select one of the plants and remove it from the ground. Leave the rest of the plants intact.
2 Rinse the roots thoroughly and remove all soil from them. Rinse off the dirt from the roots with a gentle pressure of water. Use your fingers to remove any clods of soil adhering to the roots. Then blot the roots with a paper towel.
3 Place the plant in an oven. It is best to use a drying oven to dry your plants. Set the temperature to 60-70 degrees Celsius. Keep the plant at this temperature for 8-12 hours (or up to two days) for it to dry properly.
- If you don't have a drying cabinet, you can use a fruit dryer at the same temperature.
- A conventional ventilated oven will also work. Expose it to 60-70 degrees Celsius and dry the plant for 6 hours. During this time, the plant will almost completely dry out, although some moisture will still remain in it.Do not leave the oven on overnight.
4 Place the plant in a zippered plastic bag. Close the bag tightly to keep moisture out. This will keep the plant dry. Wait for the plant to cool in the bag.
- If leaves fall off the plant during drying, pick them up. Place the leaves on the scales with the plant.
5 Weigh the plant. When the plant is completely cool, place it on the scale. Record the balance reading. After that, you can discard the plant, since drying completely destroyed it.
6 After reweighing, calculate the growth rate. You can repeat the drying and weighing procedure after a few days, but it is better to wait a week or two. After re-weighing, you can compare its results with those obtained earlier. Use the formula to find the average rate of weight gain.
- Calculate the growth rate using the following formula: ${ displaystyle { frac {(W2-W1)} {T}}}$ , where W1 is the initial weight of a dry plant, W2 is the final weight of a dry plant, T is the number of days between two weighings.

Tips

When measuring the height of a plant from the base to the top tip, do not use the ground level as the bottom reference point, as it can change depending on the amount of moisture.
Measure the plant throughout its life. Calculate the growth rate each time from your current and previous measurements. The more measurements you take, the more accurately you will determine the growth rate of the plant.
If you are interested in the amount of moisture in a plant, or if you have only one plant, measure the growth rate on a living plant. If you have many of the same plants and you do not mind losing some of them, use the dry plant weighing method.