Temperature
- Most seeds need a certain degree of warmth to germinate (sprout).
- Most plants have an optimal (best) range of temperature for growth.
- Higher: Plants have smaller leaves, thicker cuticles, and wilt is more likely to occur.
- Lower: Grow lower to the ground, have shorter life cycles, and dish-shaped leaves.
- Temperature affects moisture and nutrient uptake for the plant.
Light
- Plants need light to produce their own food through the process of photosynthesis.
- Plants use sunlight as their energy source.
- Type: Red and blue light (visible light spectrum)
- Intensity: Amount of light given off.
- Exposure: Length of time in light (photo period)
- Short day plants flower when nights are over 12 hours long.
- Long day plants flower when nights are under 12 hours long.
- Day neutral –flowering is unaffected by photo period
Water
- Water enters through the root system and carries nutrients throughout the plant.
- Water cools the plant.
- Water helps give structure to the plant.
- Keys to successful watering:
o Water all the way through the root zone for even growth.
o Pots need drainage holes to allow oxygen into the root zone.
Air
- Air contains O2 and CO2 which are both necessary for plant growth.
- CO2 is a gas that is taken in by the leaves (stomata) of the plant and is used for photosynthesis.
- Together with sunlight, the plant makes food from CO2.
- O2 is necessary for normal respiration. It enters through the roots of the plant.
Nutrients
- Plants need 16 essential nutrients to grow and produce.
Macronutrients
- The primary nutrients (macronutrients) that plants need most are:
- Nitrogen (N)
- Phosphorus (P)
- Potassium (K)
- (most fertilizers have a balance of these 3 nutrients)
Micronutrients
- The other 13 nutrients are called secondary nutrients (micronutrients).
- They are needed in smaller amounts.
- They include:
- Carbon (C) -Hydrogen (H) -Iron (Fe)
- Calcium (Ca) -Magnesium (Mg) -Zinc (Zn)
- Sulfur (S) -Manganese (Mn) -Boron (B)
- Copper (Cu) -Molybdenum(Mo) -Chlorine (Cl)
- Oxygen (O2)
