---Here are the notes from class on 23 January 2007---Updated for 12 April 2007
Climate– Temperature, precipitation, humidity, light & wind.
Seasons–What are plants doing during each season?
Spring: Most new growth, break dormancy, many flower, use stored nutrients
Summer: Maturation for most temperate plants, energy storage (mostly in root system), survival (tissue toughens, plant growth slows
Fall: Transitional time, senescence (death, plants unload energy), dormancy, seed dispersal, preparation for winter
Winter: A time of waiting, dormancy (tissue is alive but not actively growing, some plants may freeze solid (suspended animation–cells are not frozen, but the water between them is)
Cells send water out and minerals in. Concentration of minerals gets very high. Just like salt on our sidewalks freezes at a lower temperature, the cells can protect themselves in this way. They can also freeze in this state because the cell has room to expand since a lot of the water has been sent out.
NOTE: evergreens may need some additional water, but can’t always get it if the ground is frozen
—Winter damage: Frost damage, Southwest winter injury (bark damage—warms cells--they rehydrate–freeze & burst), heaving of soil (root damage), sunburn (broadleaf evergreens due to lack of water when the sun hits the leaves), rodent damage
Temperature–ranges vary from plant to plant.
Cold–Plants go into dormancy to deal with cold temperatures. They have certain thresholds of tolerance, and can withstand extremely cold temperatures since most of their functions are shut down.
--Many plants, known as frost tender plants, have a tolerance of only as low as 28 degrees F. This is the temperature where the liquid in the plants freezes and kills the plant.
--Many plant parts can be cold hardy, but the buds and blossoms can be killed if there is a frost after those parts have developed.
–Chilling requirement: Some plants, particularly one that bear fruit, have a chilling requirement. They need to have a certain number of days below a specific temperature for fruit to appear.
Hardiness zones: USDA: We are in Zone 4 b -25 to -20 degrees F
Sunset: Zone 2–growing season is early May through September, winter lows range from -3 to -34 degrees F.
Heat–Heat zone map; in higher elevations, you can find plants listed with different requirements based on the tolerance to heat. If a plant can take a certain amount of sun in one location, it may need to have more shade to be able to tolerate the sun and heat here in Utah.
Water/Precipitation–In Utah, we get an average of 13 inches of precipitation, per year. The range is 5 (semi-arid ) to 30 (high mountains)inches across the state.
Water is used to carry nutrients through the plant. It also is needed to maintain plant health due to respiration, or lose of water. Water is also necessary for the chemical reactions that occur inside all plants.
Humidity–“The amount of water air contains relative to the amount it is capable of holding at that specific temperature.” Air can hold higher amounts of water at higher temperatures. Higher humidity can help plants grow better, since they won’t lose as much water through respiration. But, lower humidity doesn’t hinder plant growth as long as there is enough water available to the roots to make up for the loss.
Light–Plants have different requirements for light. Six hours is of sun per day (morning/evening/combination) is considered “full sun”, in Utah.
–Full sun, partial shade (partial sun), Full shade
Full sun–south & west sides of house, nothing in the way to block the sun
Partial shade–direct sunlight for 1/3 to ½ of the day
Full shade–areas where the sun rarely shines directly & when the light is direct, it is in the hours when the sun is the furthest away from the earth and the rays are the weakest. (Early morning)
Day length–regulates flower initiation, vegetative growth, dormancy; acts as a cue in Spring and Winter; many plants must have a specific day length before they can flower (poinsettia, Easter Lily)
Wind–Wind can be a factor if it is too strong. It can cause damage to plants if the wrong plants are selected or improperly placed.
Soils–Cation Exchange Capacity; good structure (rather than compacted and solid) for water movement as well as nutrient availability. Soil with good texture is called friable.
A soil needs to be able to keep nutrients in it, but also needs to allow plants to take them out of it. Too much clay can make a soil have poor drainage. To change this, you can work in organic matter to improve the texture & change the cation exchange capacity as well. Texture is determined by the amount of sand, silt, and clay. Organic matter can also affect the texture of the soil.
pH–Acidity or alkalinity of the soil. Most plants need near a pH of 7 (neutral) to grow and develop properly; nutrient uptake is greatly affected by pH. In Utah, you can’t change the pH very much, due to the high amounts of calcium in the soil. Calcium acts as a buffer.
Oxygen–The plant’s roots need oxygen to respire. If the soil is over-watered, or if there is inadequate drainage, the roots cannot receive the oxygen they require and will eventually rot.
Nutrients–Carbon, Hydrogen, Oxygen |Nitrogen, Potassium, Phosphorous | Calcium, Magnesium, Sulfur | Boron, Chlorine, Copper, Iron, Manganese, Molybdenum, Zinc
C, H & O are available in the soil and air and don’t need to be added.
N, P & K are called primary nutrients–they are usually lacking before the others because they are needed the most, after C, H & O. They need to be added.
C, Mg & S are called secondary nutrients–They are usually available in the soil, but need to be added sometimes.
The rest are known as micronutrients. Plants only need them in very small amounts. Some of these, like Iron, can be tied up in the soil and need chelating agents to make them available. (pH causes iron to be tied up.)
Macronutrients get tied up in the soil more often in soils with low pH.
Micronutrients get tied up in the soil more often in soils with high pH.
If a plant is lacking in certain nutrients, there are specific symptoms that can be used to diagnose the problem.
Composting–Organic materials are converted into soil conditioner by making the conditions right for them to break down. Humus is what it is called when the process is complete.
Organic Matter –When worked in, it can improve friableness, drainage & nutrient holding capacity. Can be gained by adding composted material, mulches, or other products available to buy.
Composting–Choose a level, well-drained site. Build your pile over soil or lawn to make use of earthworms.
Tools: Compost thermometer, compost bin, aerator
If you just add to a pile and don’t manage it, you’ll have a slower decomposition. It may take a year or two. If you do everything that you can, you’ll have a fully composted pile in 3-4 weeks. You can either put everything together all at once and work that pile or continually add to it. The latter will take longer since new materials are added.
Factors: All organic matter will decompose, but the following guidelines will speed up the process.
Carbon to nitrogen ratio (C:N)–the carbon is the “food” and the nitrogen functions as the digestive enzymes. The ratio should be 30:1 by weight. Accomplish this by adding 3-4 pounds of nitrogen material for every 100 pounds of carbon material. Not enough nitrogen will slow the decomposition process and too much can cause foul odors. Carbon: Leaves, newspaper, cardboard, sawdust, etc. Nitrogen: Manure, grass clippings, plant parts. Be careful with diseased plants and weeds. These can be added, but you need to make sure it gets hot enough to kill any diseases or weed seeds. (www.compostguide.com has a great chart listing material to be used and what not to use as well as why or why not.)
Surface Area–Cutting, chopping or otherwise making the materials in a compost pile smaller will enhance the surface area. With more surface area, the material will have more access to oxygen. Microbes can then have more access as well.
Aeration–Decomposition uses up the available oxygen. For the process to continue, more oxygen needs to be added. A compost pile needs to be turned to place the decomposing material in contact with new oxygen. The microbes will also have more access to the material.
Moisture–Microorganisms can only decompose organic materials if there is water present. The moisture content should be 40-60%. If water content goes below 40%, decomposition may stop completely. If the level is above 60%, aeration stops, nutrients can be leached out and the pile will smell. If you squeeze a handful of the compost, it should feel like a wrung-out sponge.
Temperature inside pile–The temperature should range between 90 and 140 degrees. If it is higher or lower, decomposition will slow.
Temperature outside pile–Though you can’t change the outside temperature, it will affect the temperature inside the pile. Spring is the best time to start composting. You can also improve the outside temperature by choosing a sunny, protected area.
Pollination–For fruit/seed production to occur, pollination must occur beforehand. Some plants can pollinate themselves, but others need to be pollinated by other plants. Bees, birds & wind can accomplish this.
Microorganisms–There are many microorganisms active in the soil. Some of these can provide benefits to plants. Some can make some of the essential nutrients more available to the plants by converting them into the forms that are more available to plants. Iron and Sulfur are two elements that are affected by microbes.
Microclimates–Areas that have different conditions than the surrounding land. This can be a temperature, wind, sun, moisture or any other condition, difference. This can be a beneficial or detrimental difference. If it is beneficial, you may be able to grow something that you can otherwise grow in your yard. The reverse is also true. Microclimates can be created by natural things such as trees, or hills. They can also be created by things that you do, such as plantings, fences, or buildings. Paint color or the material chosen for a fence/ building can make an area warmer if it is very light or made of glass.
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