Plant Growth & Development

  1. What is soil
  2. Soil – mixture of rock (inorganic materials), waste and remains of soil organisms (organic matter) air and water
  3. Where does soil come from?
  4. Rock that has been broken down into smaller pieces by weather and organisms
  5. This is a constant process
  6. It takes a long time to make soil
  7. Components of soil
  8. Rock an other types of inorganic material
  9. This is 45% of soil
  10. Gives roots something to hold onto
  11. Made of sand(largest), silt and clay (smallest)
  12. The amount of sand silt and clay determines soil type

More large particles bad because doesn’t hold water and nutrients [loam] more small particles bad because no O2 and poor drainage

  1. Inorganic matter helps heavy water logged soils to drain better
  2. Pearlite – mined glass that has been heated to high temperature and puffed
  3. improves drainage but does a poor job of holding water
  4. floats, bad to inhale, takes a lot of energy and pollution to create
  5. this is a OMRI certified organic product
  6. Vermiculite – flakes of asbestos and rock
  7. Lightens soil and improves drainage while holding onto water
  8. Super bad to inhale and super bad for the environment to create (strip mined in asbestos mines)
  9. this is a OMRI certified organic product
  10. Sand – rock that is ground to particles smaller than ______
  11. Does not lighten soil, makes small improvement to drainage
  12. Good for the environment, and cheap
  13. this is a OMRI certified organic product
  1. Organic matter/humus– made of animal droppings and dead plants and animals
  2. As fungus and bacteria break down the animal droppings and dead organisms it add nutrients to the soil
  3. Organic matter adds nutrients to the soil as soil fungus and bacteria break it down, and helps soil hold onto water
  4. Compost – a mixture of fully degraded leaves and other plant products
  5. Holds lots of water, creates its own natural fertilizer over time as it breaks down into soil
  6. May not be OMRI certified organic or safe to use on edible crops depending on the origin of the plants that made it
  7. Bags of humus sold in stores are usually a mixture of compost, manure, and other materials that increase the organic material in soil
  8. Peat moss – partially composted dried moss
  9. Peat moss helps soil hold onto water, and increases the acidity of soil
  10. Peat moss adds very little nutrients to the soil, and can make the soil too acidic for most plants
  11. Because of constant harvesting over the past 100 years, the living organisms that create “peat moss” are now considered to be endangered
  12. Manure – partially or completely decomposed animal droppings
  13. Manure of different animals adds different nutrients to the soil so it is possible to provide the plants with nutrients they don’t need by mixing manure into the soil
  14. Manure of carnivores is very dangerous to have in soil (dogs, cats, humans, some pigs) because the same parasites in their manure that make them sick can be absorbed by the plant and make us sick. (E.coli from lettuce or spinach). This is also now happening with cow manure
  15. Raw droppings in any form should not be added to plants directly because it is only in the biological degradation of waist that fertilizers are produced witch are useful to plants
  16. Some animals (horses especially) have incomplete digestive systems that passed seeds straight through without harming them so, using citron types of manure is like sowing weeds in your garden
  17. Earthworm castings (earthworm poop)is some of the most nutrient rich safe manure a grower can use, but it is also expensive
  18. Air and water
  19. This is 50% of the soil
  20. The more air soil has the less water and the more water soil has the less air
  21. Soil air is high in co2 from respiration that happens in the roots.
  22. As water drains through soil it pulls in oxygen from above the soil into the soil
  1. Improving soil
  2. Plants grow heather and taste better when soil is correct
  3. The best soils drain well, but also retain moisture so the plant roots don’t completely dry out in the heat
  4. Drainage = more inorganic components
  5. Retain moisture = move organic components
  6. Therefor the best solid have the right ratio of organic and inorganic components
  7. Types of soils
  8. Seed starting soil – a very light well-draining soil that is designed to help seedling start to root
  9. Potting soil – a heaver soil designed for potting plants. This soil holds onto water better because pots dry out a lot faster than ground
  10. Top soil – a bag of soil that “someone” thinks would be best for “most plants”
  11. Gardening soil – usually a very heavy mixture decomposed organic matter that helps increase the nutrients in preexisting soil
  12. Specialty soils
  13. Lawn soil – top soil with more nitrogen in in that helps lawns
  14. Orchid soil – since most orchids sold in stores don’t grow in ground but instead grow on trees, this is just a bag of chunks of tree bark
  15. African violet soil –a acidic soil that absorbs and holds onto water well
  16. Cactus soil – a well-draining soil that has less nutrients
  17. Acidic or basic soil
  18. The pH of soil effects how plants absorb water and nutrients
  19. Most plants prefer soil to be neutral (at or around a pH of 7) because this is the range where most of the nutrients plants need become dissolved in soil water and become available
  20. When soil is too acidic or basic plants become malnourished and begin to die
  21. Too much acid in soil dissolves and washes away all the available nutrients
  22. Too much base in soil binds up all the nutrients so plants cant dissolve them
  23. Plants that like acidic soils = berries, pines and evergreens, holly’s, gardenias, begonias, ferns
  24. Plants that like basic soils = cactus and succulents, boxwoods, baby’s breath, carnations, lilacs, monkshood, oregano
  25. To make soil more acidic you can add gypsum/sulfur, or peat moss
  26. To make the soil more basic you can add lime
  1. Nutrients in soil
  2. Nutrients – elements that plants absorb form the air, water or soil that they need to live
  3. There are 19 essential nutrients that all plants need
  4. 7 of the 19 nutrients plants need lots of and are called macronutrients
  5. 12 of the 19 nutrients are micronutrients and plants only need small amounts of them

Nutrient / Where the plant gets it / Function / Too much / Not enough
Carbon, hydrogen, oxygen / Air and water / Plats use these nutrients to make the fats, proteins, and carbohydrates they need to survive / No effect / Plant will die
Nitrogen / Soil / Helps the vegetative body of the plant (roots, stems, leaves) / Plant will be all leaves and no flowers or fruit / The plants leaves turn yellow
Phosphorous / Soil / Helps the reproductive body of the plant (fruits and flowers) / The plant will flower but not have enough leaves to support or develop the fruit / Plant wont flower, the edges of the plants leaves will turn red
Potassium / Soil / Helps the plant absorb and store water and nutrients / No bad effect / The edges of the plant leaves will turn yellow and die
Calcium / Soil (adding egg shells) / Helps the plant cells to stick together the plant or fruit doesn’t get mushy / Makes soil too basic / The bottoms of the fruits of the plant begin to rot on the vine
  1. 12 micronutrients, (Cl, Fe, B, Mn, Na, Zn, Cu, Ni, Mo) are mostly used to help the plant photosynthesize and go through cellular respiration
  1. How do nutrients get into the soil in nature
  2. In nature, nutrients are removed buy living plants and put back into the soil through plant death and decay
  3. When plants are harvested for sale, the nutrients removed by the plants never make it back to the soil, and overtime the soil becomes more and more nutrient poor. (also when a lawn is mowed and the clippings are removed)
  4. To keep farm land fertile over time you must add nutrients in the form of fertilizer to the soil
  5. All fertilizer is mainly a combination of 3 macronutrients, N, P, K, and all fertilizer has 3 numbers that tell you the quantities of each nutrient in the fertilizer
  6. In general, plants can only absorb so much nutrients at once from the soil so they don’t need anything over 5% of any nutrient at once, and too much would just salt the soil
  7. Types of fertilizer
  8. Organic fertilizer – fertilizer that contains only ingredients that come from natural living organisms
  9. Myths of organic fertilizer:
  10. Pros: Lasts longer, Helps plant resist disease, Improves soil over time
  11. Cons: More expensive, Exact composition unknown, Decreased plant production
  12. Organic disclaimer: plants grown organically produce chemically identical fruit. Fruits and vegetables labeled as organic are no better or worse for you than conventionally grown fruits and vegetables. They are more expensive because the farmer producing them usually produces less and gets less government subsidies as an organic farmer. (Cuba vs. US food production) Organic farmers use the same types of chemicals that conventional farmers use, they are just not produced in a lab but instead come from natural products. (pyrethrum vs. carnations) What is true is that organic farms have much less of an environmental impact than conventional farms. In fact whereas a conventional farm destroys soil over time, organic practices improve soil over time producing continually heathier and heathier crops that need less and thus cost less to grow
  13. Organic fertilizers
  14. Blood meal – dehydrated blood of animals that have been slaughtered and cooked at high temperatures
  15. Bone meal – the burned ash of animal bones
  16. Green sand – a mined mineral (iron potassium silicate) that dissolves in water and adds both iron and potassium to the soil
  17. Conventional fertilizer – fertilizer that has been manufactured in a lab through mixing chemical compounds
  18. Pros: Fast, Inexpensive, Know the exact chemical makeup
  19. Cons: Changes soil pH, Makes soil too salty, Often has more fertilizer than plants can absorb, Surge in plant growth may weaken plant over time, Need to apply multiple times per season
  20. Organic vs conventional growing
  21. Both use chemicals (pesticides, fungicides, herbicides)
  22. Both produce chemically identical food
  23. Organic = used no chemical that was made in a lab. Less food was produced but because of that the overall quality of the food goes up, environmental impact was minimalized, and it is more expensive
  24. Conventional – more food, more pollution, less expensive
  1. Hydroponics and vertical gradining
  2. Hydroponics – soilless growing where nutrients are provided to the plant roots through a nutrient solution.
  3. Types of hydroponic systems:
  4. Traditional hydroponics - Nutrient solution is sprayed or misted on the roots
  5. Aquaponics- Nutrients are generated by the waste of fresh water fish organically
  6. Aeroponics- Nutrient solution makes direct contact with roots
  1. Advantages of hydroponics:
  2. no herbicides or fungicides, or insecticides
  3. plants grow faster and healthier with higher yields because they spend less energy looking for water and nutrients in the soil
  4. Disadvantages of hydroponics :
  5. Plants are slower to start
  6. Dependent on inorganic industrial produces fertilizing salts
  7. Requires lots of infrastructure
  8. Vertical gardening - growing container plants in layers vertically instead of horizontally
  9. Advantages:
  10. Takes less space for much greater increase in yield
  11. Most efficient use of water runoff in that many layers of plants have the opportunity to absorb excess
  12. Plants can be grown in soil
  13. Disadvantages:
  14. Careful planning needs to be taken to make sure plants get enough water and sunlight
  15. Plants generally grow worse as they need to spend lots of energy righting themselves upwards after growing out of a wall