Auxins are plant hormones that regulate cell growth and development.
Auxins are found at the tips of twigs, roots, and buds. Auxins are the reason roots go down and stems go up. They also restrict buds lower down the stem from developing. When these tips are cut off, lateral bud development further down the stem increases, which means more fruit or flowers.
Many herbicides are actually synthetic plant hormones that force a plant to grow so fast that it dies.
Auxins travel through the stem downward, through the phloem, so gardeners can bend branches into a more horizontal position to reduce auxin levels and stimulate lateral bud growth.
Cotyledons are the first leaves that appear when a plant emerges from seed.
Cotyledons rarely look like the adult plant's leaves, as you can see in this photo:
Vermiculite is a brownish silicate mineral commonly used to help create air spaces in soil, which improves drainage and nutrient movement.
A layer of vermiculite is often placed over newly planted seeds, in pots. This helps retain moisture, which improves germination without encouraging fungal diseases, such as damping off disease.
Soilless growing medium
Vermiculite is also a component of soilless growing medium. Combined with materials such as peat or composted bark, this mixture provides a very light medium, filled with water, air, and nutrients, making it easy for new roots to become established.
Root and bulb storage
If you store root crops or bulbs over the winter, keeping them in a bed of vermiculite can stabilize moisture levels, preventing rot.
Because it is so light, vermiculite can be mixed with heavy clay to create more macropores and micropores. This improves soil structure, making it easier for roots to move through the soil.
With all of those good characteristics, you would expect more people to use vermiculite, right?
Unfortunately, until 1990, many sources of vermiculite contained asbestos. Pure vermiculite does not contain asbestos, but there is no way to be 100% sure that the vermiculite in the bag at the garden center hasn’t absorbed asbestos or some other harmful chemical. Using it in small doses is probably fine. I prefer renewable resources, such as aged compost, which I know is healthy for everyone involved.
Urban drool is the water that runs off improperly watered lawns, carrying fertilizers, pesticides, and valuable nutrients to ground water, local streams and the ocean, causing potentially devastating bacterial and algae blooms and chemical pollution.
To avoid urban drool, think of how a dry sponge absorbs less water than a damp one. Urban drool can be prevented by watering with hourly pulses of short durations that give the soil enough time to absorb the water.
Thigmomorphogenesis is the response of plants to touch (thigmo is Greek for touch).
As plants follow the sun and brace themselves against the wind, they become stronger. This means plants grown in greenhouses tend to be taller and weaker than plants grown outside. To keep these overly protected plants healthy, many greenhouses use machines that knock the plants over, in different directions, several times a day. Cool, huh?
You can grow a surprising amount of food in your own yard. Ask me how!