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chuckga
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« on: February 02, 2010, 01:52:40 PM » |
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Plants need an adequate level of nutrients to thrive. The purpose of this post is to provide you with information to assure that your plants receive the proper levels of all nutrients for optimum yield and quality.
Nutrients
Three key nutrients for plant growth are nitrogen (N), phosphorus (P) and potassium (K). These nutrients are contained in most commercial fertilize mixes. Other materials you may need to add are lime, sulfur, magnesium, and boron.
Nitrogen is important for healthy plant growth. It needs to be applied each year because rain and irrigation remove most of the nitrogen not used by plants. Plants use the most nitrogen during or just before the time of rapid growth. For most plants this is the best time to add nitrogen. If you apply nitrogen late in the growing season, most plants cant efficiently use it and the excess will remain in the soil after the growing season allowing winter rains to leach the nitrates into the soil below the root zone.
Phosphorus is essential for vigorous growth of seedlings, especially in cool, wet, spring weather.
Potassium is important for disease resistance and starch formation.
Soil pH
Soil pH is a measure of how acidic or alkaline a soil is. A soil with low pH (below 7.0) is acidic, while a soil with high pH (above 7.0) is alkaline(basic).
| Acidic | Alkaline |
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0 7 14
Vegetable gardens produce well in soil pH of 6.0 - 7.0. "Acid loving" plants such as potatoes, azaleas, blueberries, and rhododendrons require a soil pH below 6.0 and prefer 4.5 to 5.5. If soil pH is too low, add lime to make the soil less acidic. Use 5 to 10 pounds of lime per 100 square feet if mixing into the soil before planting. Retest soil 3 to 6 months later to see if you have achieved the target pH levels.
Types of fertilizer
Opinions vary concerning the merits of manures or other organic fertilizers versus "chemical" fertilizers. Excellent gardens may be grown using either method or a combination of both. Plants do not differentiate between nutrients from organic and chemical fertilizers; the form absorbed by plants roots from both sources is identical.
Plants can use chemical fertilizers as soon as they are applied. Soil bacteria and fungi must act on most organic nutrients to change them into a usable form. Thus if you use mostly organic fertilizers, you may need to add a small amount liquid fish, blood meal, or chemical fertilizers early in the season in order to ensure adequate plant nutrition until the organic fertilizers become available to plants.
Packaged mixes
Both chemical and organic fertilizers are available as packaged mixes, containing N,P,K, and sometimes sulphur (S). Package labels tell how much of each nutrients the fertilizer contains. The nutrients are always listed in the following order: nitrogen-phosphorus-potassium. A fertilizer labeled 5-15-10 contains 5 percent nitrogen, 15 percent phosphorus (in the form of phosphate), and 10 percent potassium (in the form of potash). In other words every 10 pounds of this fertilize contains 0.5 pounds of nitrogen, 1.5 pounds of phosphorus and 1.0 pounds of potassium. If a forth number is listed, it represents sulpher. Thus a 5-15-10-10 also contains 10 percent sulpher (in the form of sulfate). The remaining components of the fertilizer (Minors) include carbon, hydrogen, oxygen and coating materials.
Unblended organic sources
Wood Ash
Wood ash is a good source of potassium. You can use as a fertilizer and liming material on vegetable gardens, flower beds, lawns, and most shrubs. It is also useful in acid soils (pH 0 to 7) low in potassium. The fertilize value of wood ash depends on the type of wood burned. Generally hardwood weighs more per cord than softwood and yields more ash per pound of wood. Hardwood also contains higher percentages of nutrients.
Ash from a cord of oak meets the potassium needs of a garden 60 feet by 70 feet (4,200 square feet), and ash from a cord of softwood (Douglas-fir) meets the potassium needs of a garden 30 feet by 30 feet (900 square feet). Both contain enough calcium and magnesium to reduce soil acididity slightly. Elements in ash are water soluble, therefore always store ash in a dry place until you are ready to use it.
Apply wood ash evenly, and if possible mix them into the soil. Never leave ashes on the surface in lumps or piles. If ashes are concentrated in one place, excessive salt leaches into the soil, creating a harmful environment for plants.
Be aware of several precautions if you use wood ash;
Do not to exceed 20lbs, roughly 5 gal bucket, per 1000 sq ft per year...because of potential salt build up in the soil
Do not apply wood ash to acid loving plants such as potatoes, blueberries, rhododendrons, and azaleas.
You may have problems with potato scab, a fungus disease, if you use ash where you grow your potatoes.
Do not add fertilizer containing nitrogen in the form of ammonium immediately after adding wood ash. this can result in a loss of ammonia.
Do not add wood ash to newly germinated seeds.
Do not use ash from coal, lead painted or chemically treated wood, or ash where trash has been burned.
If the potassium soil test value is 600 ppm, do not apply wood ash for 5 years.
Grass Clippings
A 6 to 8 inch layer of grass clippings can be added to gardens as a fertilizer material. Grass clippings are a good source of potassium. Do not use fresh clippings from weedy lawns, bentgrass lawns, or turf with rhizomes. These sources may introduce weeds and unwanted grass.
Manure
Manure can modify the soil structure and water-holding capacity of a garden. These benefits are often greater than the nutrient benefits of manures. Organic matter improves soil structure, increases the water holding capacity of course textured sandy soils, improves drainage in fine textured clay soils, provides a source of slow release nutrients, reduces wind and water erosion, and promotes growth of earthworms and other soil organisms.
Fresh (non-composted) manure is high in soluble forms of nitrogen, which can lead to salt build-up and leaching losses if over applied. Fresh manure may also contain high amounts of weed seeds, which can lead to weed problems. In addition various pathogens such as E. coli may be present in fresh manure and can cause serious illness to individuals eating fresh produce unless proper precautions are taken. Apply and incorporate raw manure in fields where crops are intended for human consumption at least three months before the crop will be harvested. Allow four months between applications and harvest of root and leaf crops that come in contact with the soil. Heat generated during the composting process will kill most weed seeds and pathogens, provided temperatures are maintained at or above 131 degrees F for 15 days or more (and the compost is turned so that all the material is exposed to this temperature for a minimum of 3 days). (Source: University of Minnesota, Agricultural, Food and Environmental Sciences) Apply fresh manure in the garden only in the fall after crops are harvested..
Gardner’s need to understand that the nutrient release from compost and manure is slow, taking years. Adding compost or manure to improve soil tilth is not the same as fertilizing.
The typical nitrogen release rates from manure is only 30 to 50% the first year (fresh manure), 15 to 25% the second year, 7 to 12% the third year, 3 to 6% the fourth year and so on. With compost and composted manure, the release rate is even slower, 5 to 25% the first year, 3 to 12% the second year and 1 to 6% the third year.
For soil with 4% to 5% organic matter, the release of nitrogen from soil organic matter will likely be sufficient for crop growth.
For soil with 2% to 3% organic matter, the release of nitrogen will not likely be sufficient for heavy feeding vegetable crops. Supplement with 0.1 pound nitrogen fertilize per 100 square feet.
For the typical garden soil with 1% organic matter, the release of nitrogen will be minimal. Add 0.2 pounds of nitrogen fertilizer per 100 square feet.
Refer to post: "Manure nutrient Chart"
Blood Meal
Blood meal applied at 1.5 to 2 pounds per 100 square feet is another good source organic nitrogen.
Methods of applying fertilizer
Three ways to apply fertilizer are described below. Regardless of the method you use, keep the following facts in mind;
* The nitrogen in chemical fertilizers is highly water-soluble and is carried to the roots by irrigation or rain. Thus, you don’t need to mix these materials into the soil, but you do need to water your garden if rain doesn't fall within a day after you apply them.
* Organic sources of nitrogen are most accessible to plants if mixed into the top 2-3 inches of soil.
* Phosphate moves slowly in the soil. You will obtain the best results by blending phosphate-containing fertilizer 2 inches below the seed when you plant or by tilling it into the soil during spring preparations.
* Work potassium fertilizers into the soil using the banding or broadcast methods. Do not allow potassium fertilizers to contact plant roots.
Do not place fertilizer in the seed row or root damage may occur.
Broadcast
Scatter the material uniformly over the surface. If an application method is not mentioned, broadcasting is implied.
Band
Place the fertilize in a trench about 3 inches deep. The corner of a hoe works well to make the trench. Sow seeds 1 1/2 to 2 inches above and to the side of the fertilizer. The plant roots quickly absorb the nutrients and grow rapidly.
Sidedress
Scatter the fertilizer material close to the growing plants. Keep the fertilizer granules off the leaves to prevent burning. Nitrogen is very soluble and need not be mixed with the soil. A fertilizer blend containing nitrogen, phosphate, and potash should be lightly scratched in, but take care to avoid damaging plant roots. Apply irrigation so plants can absorb the nutrients or apply prior to a rain.
Nitrogen Application Rates
Application rates are critical, because too much or to little directly impacts crop growth. The standard annual application rate for home vegetable gardens is 2 pounds actual nitrogen per 1,000 square feet (0.2 pounds actual nitrogen per 100 square feet). When organic matter is supplied, adjust the rate accordingly to account for nitrogen released by the organic matter. See the following chart;
Soil Organic Content
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Typical garden soil Moderate level of High level of
low in organic matter organic matter organic matter
(1% organic matter) (3% organic matter) (5% organic matter)
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Nitrogen needed 0.2 lb actual N 0.1 lb actual N 0
per 100 sq. ft. per 100 sq. ft.
Fertilizer examples
Ammonium sulfate 1 lb. fertilizer 0.5 lb. fertilizer
21-0-0 per 100 sq. ft. per 100 sq. ft. 0
(approx. 2 cups) (approx. 1 cup)
OR
Ammonium nitrate 0.6 lb. fertilizer 0.3 lb. fertilizer
34-0-0 per 100 sq. ft. per 100 sq. ft. 0
(approx. 1 1/3 cups) (approx. 2/3 cups)
OR
Urea, 45-0-0 0.4 lb. fertilizer 0.2 lb. fertilizer
per 100 sq. ft. per 100 sq. ft. 0
(approx. 1 cup) (approx. 1/2 cup)
Nitrogen "Side Dressing"
Plant need for nitrogen varies. Beans, peas, tomatoes, and vine crops (cucumbers, squash, pumpkins, and melons) are examples of vegetables with a lower need for nitrogen. High nitrogen promotes excessive growth of the plant at the expense of fruiting.
Crops such as potatoes, corn, cole crops (broccoli, califlower, cabbage, and kale) use large amounts of nitrogen and need supplemental applications during the growing season (referred to as side dressing). Fertilizers commonly used in home garden for side dressing include ammonium sulfate, ammonium nitrate, and water-soluble fertilizers such as MiracleGro, Peters, etc. Phosphate and potash fertilizers are best added in the spring or fall, when they can be cultivated into the soil.
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| Application Rate
|(Based on rate of 0.1 lbs. actual N per 100 square feet)
|---------------------------------------------------------
|Ammonium sulfate Ammonium nitrate Water Soluble
Vegetable Timing | 21-0-0 34-0-0 fertilizers
-----------------------------------------|-----------------------------------------------------------
Asparagus 1) early spring |0.5 lbs. fertilizer 0.3 lbs. fertilizer per See label of
2) at end of harvest |100 sq. ft. 100 sq. ft. specific
season |(approx. 1 cup) (approx. 2/3 cup) product
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Sweet Corn 1) 12" tall
2) one month later
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|Sprinkle over soil and
Leafy Green 3-4 weeks after emergence |water in, OR place in
vegetables |furrow to side of plant.
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Onions 3-4 weeks after emergence |CAUTION: an over
-----------------------------------------|application will burn
Potatoes 12" tall |roots, stunting or
-----------------------------------------|killing plants.
Tomatoes, |
peppers, and First fruits 1" diameter |
eggplants |
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Cloe Crops 1) 2-3 weeks after |
(broccoli, transplanting |
cabbage, 2) 4-5 weeks after |
cauliflower) transplanting |
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Some Handy Conversions
To convert from; To: Do This;
100 square feet 10-foot row Divide the 100-square foot rate by 10.
100 square feet 1 large plant (e.g. tomato) Divide the 100 -square foot rate by 20.
100 square feet 1 smaller plant (e.g. broccoli) Divide the 100 -square foot rate by 40.
15-15-15 fertilizer 10-10-10 fertilizer Multiply the 15-15-15 rate by 1.5.
15-15-15 fertilizer 7-3-2 fertilizer Multiply the 15-15-15 rate by 2.
15-15-15 fertilizer 5-5-5 fertilizer Multiply the 15-15-15 rate by 3.
21-0-0 fertilizer 10-10-10 fertilizer Multiply the 21-0-0 rate by 2.
21-0-0 fertilizer 7-3-2 fertilizer Multiply the 21-0-0 rate by 3.
21-0-0 fertilizer 5-5-5 fertilizer Multiply the 21-0-0 rate by 4.
pounds of fertilizer cups of fertilizer Multiply the pounds by 2.
3 cubic yards (67 bushels) covers 1,000 square feet aprox. 1 inch deep.
The standard annual application rate for home vegetable gardens is 2 pounds actual nitrogen per 1,000 square feet (0.2 pounds actual nitrogen per 100 square feet).
(Primary source: Oregon State University Extension Service... "Fertilizing your garden")
(Source: Colorado State University. Soil Management and Fertilization)
(Source: University of Minnesota, Agricultural, Food and Environmental Sciences)
(Sources: Livestock Waste Facilities Handbook 2nd edition 1985)
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