Duration: 50 minutes
Students will plant garlic and understand why we plant garlic in the fall; learn about bulb anatomy and lifecycle.
Bulb life cycle
Is this the season we usually plant in our area? Garlic is planted in the fall for roots to grow before winter. Garlic needs several weeks of cold soil in the winter before they can grow. In the spring, the plant will grow.
Why is the bulb an adaptation for a plant? A bulb is an underground modified stem that functions as food and water storage tissue for the plant to survive through a cold or dry season.
Anatomy of an onion
- What is the purpose of the skin on the outside? The skin on the outside protects the bulb from damage or drying out underground. It acts like a coat or skin to protect the bulb. The thin outer skin on a bulb is the tunic.
- Show the inside of the onion. Under the tunic are layers of scales. Can you guess the reason for the layers? Scales are leaves that provide food for the bulb. What is the purpose for those layers? The onion layers are food. Just like food helps us grow, the layers inside the bulb are food to help the bulb grow a plant. The scales fit together like layers of an onion and provide food to the developing plant.
- The scale leaves are held together by the basal plate, which is located at the bottom of the bulb. The basal plate is a short stem. The new plant and new bulbs grow from the basal plate. In the spring, roots grow down from the basal plate. The basal plate holds the bulb together. Which end is planted down?
- Do you see anything else inside the bulb? Help the students notice the greenish/yellowish center. This is the embryo, or the new plant, that will grow in the spring. The new plant is protected in the layers and gets nutrients from the layers to push through the soil in the spring. The embryonic plant develops from the center of the basal plate, and grows up and out of the top of the bulb. The parts of the plant that can be seen inside are the flower bud, stem, and leaves.
- Where is the seed? Seeds form from pollinated flowers. Bulbs can be grown from harvested seeds, but the period from seed planting to blooming flower is several years. In the case of a daffodil, the period of seed germination to blooming flower is five years. For a tulip, the period is 5-7 years. Bulbs that are too small will not produce flowers, but will produce leaves.
More about garlic
- Garlic is in the allium family which includes onion, leek, chive, and shallot.
- Northern California grows most of the garlic in the United States.
- Cultivated garlic plants do not set flowers that produce true seeds.
- Garlic bulbs are wrapped in a papery tunic. Roots grow from the basal plate at the bottom of the bulb. Inside the bulb, cloves are attached to the basal plate. Cloves are similar to seed leaves in a true bulb, but each is wrapped in its own tunic-like covering and each has an embryonic plant inside. Individual garlic cloves are not layered.
- Hardneck garlic varieties of garlic grow a flower stalk called a scape. Flowers are short-lived and small bulbs called bulbils form. Hardneck varieties generally grow better in cold climates. Bulbs produce 4 to 8 large cloves.
- Generally, softneck garlic varieties do not form a flower stalk. Grocery store varieties are usually softneck. Bulbs produce 12 to 20 cloves.
- True seeds are not developed, so individual cloves or bulbils are used for planting. Bulbils will produce small bulbs the first year.
- Garlic is best planted in fall for cloves to develop roots before winter and for the cloves to go through a cold period for optimum growth in spring.
- Garlic is nicknamed the stinking rose. No one is sure why, but the nickname is believed by some to originate with a Greek word that was translated by a Frenchman to mean stinking rose.
- Garlic is thought to prevent the common cold and flu and to repel mosquitoes.
- soil ammendments
- planting knives
- basal plate
- Is this the season we usually plant in our area? Garlic is planted in the fall for roots to grow before winter.
- Explain that the students will plant garlic. A garlic bulb has a tunic and basal plate. Garlic has individual cloves instead of scales inside the bulb, but serves the same function. The stem in the middle of the cloves is the stem of the plant that produced the head of garlic. Each clove has a plant inside. Students will plant a clove to grow a new plant. Garlic bulbs are able to live through cold soil conditions in our winters. They need a period of cold temperature dormancy to grow in spring.
- What is the purpose of the skin? The skin on the outside protects the bulb from damage or drying out underground.
- What is the purpose of the cloves? They serve as food to feed the new plant.
- Which end do you plant down? The flat end- called the basal plate.
- Separate the cloves CAREFULLY so as not to harm the “tunic”.
- Drop worm castings/compost hand-fulls on 8” centers- with rows about 8”-12” apart.
- Mix in the worm castings well.
- Plant each clove in the prepared soil with the POINTY END UP.
- Mulch with leaves or straw to keep the soil warmer (prevent extreme freeze/thaw) and moderate soil moisture.
- Have students guess which end is planted down. It will be the basal plate.
- Plant a few of the small cloves in pots and put in the classroom. Dig up a clove in one week, then two, then three to examine root growth.