Raising or Lowering the pH in the Soil Mix

Growing in soil and adjusting pH levels

A lot of gardeners have trouble with the pH of their soil. A high pH can lock out needed nutrients and mimic other problems like Fe and Mg deficiencies. The biggest mistake new growers make is to try and correct pH problems too quickly. The first step in determining if high pH is the real problem, is to pick up a good pH tester. Don't be afraid to shell out the cash for a good one, it's well worth it!

What is pH, and what do the terms acidic and alkaline mean?

The acidity or alkalinity of the soil is measured by pH (potential Hydrogen ions). Basically it's a measure of the amount of lime (calcium) contained in your soil, and the type of soil that you have. A soil with a pH lower than 7.0 is an acidic soil and one with a pH higher than 7.0 is considered to be alkaline. A pH of 7.0 is neutral.

Adjusting your soil pH :

Once you have determined the pH of your soil with a good tester, you can amend the soil if needed to accommodate the plants in your garden using inexpensive materials commonly available at your local garden center.

Adjust soil pH slowly over several days time, and check pH often as you go. Radical changes in pH may cause osmotic shock damage to the roots.

Raising soil pH : (to make it more alkaline)

It is generally easier to make soil mixes more alkaline than it is to make them more acidic. The addition of dolomite lime, hardwood ash, bone meal, crushed marble, or crushed oyster shells will help to raise the soil pH.

In soil: add dolomite limestone to the soil; use small amounts of hydrated lime.

Raising hydroponic pH : (to make it more alkaline)

In hydroponics: use potassium silicate, provides silicon at an effective dosage. In bioponics/hydro-organics: add small amounts of sodium bicarbonate or lime.

Lowering soil pH : (to make it more acidic)

If your soil needs to be more acidic, sawdust, composted leaves, wood chips, cottonseed meal, leaf mold and especially peat moss, will lower the soil pH.

bloodmeal/cottonseed meal during vegetative; bonemeal during flowering.

Lowering hydroponic pH : (to make it more acidic)

In hydroponics: use nitric acid during vegetative; phosphoric acid during flowering.

Stabilizing pH with Dolomite lime:

The best way to stable pH is by adding 30 gms of Dolomite Lime to around 5 kg of planting soil. Buy the fine Dolomite powder (There may be several kinds of Dolomite like Rough, Medium, Fine) Dolomite Lime has been a useful pH stabilizer for years, since it has a neutral pH of 7 when added to your soil it stabilizes your soil at pH 7.Mix the dry soil medium and dolomite together really well, give the mix a good watering then after the water has had chance to settle and leech into the soil a bit give the mix a really good stir. Then water the soil/lime mix and give it another stir. Best plan is to mix fine dolomite lime into your mix before planting. Fine Dolomite will help stabilize your pH; however, if the ph becomes unstable or changes, you can then use Hydrated Dolomite Lime. Add some of the hydrated lime to luke warm water and give it a good stir then water your plants with it. Give the plants a good watering with this hydrated lime added and your pH should fall or rise back to 7.

Dolomite lime is also high in two secondary nutes that can often be overlooked by fertilizers; dolomite is high in both (Mg) Magnesium and (Ca) Calcium.

Source : www.kindgreenbuds.com

My Garden Sep 2015

First Ridge Gourd & Pomegranate of the season

First Cucumber of the season in my TG

This photos I posted in Chennai Terrace Gardeners' Forum in Facebook, showing how the Hibiscus was on 3.8.2015, when it was fully affected with Mealy Bugs and on 3.9.2015, it fully recovered after giving kerosene treatment.

Vallarai, Mudakkathan, Pasalai Keerai, Palak & Brinjal

Palasalai Keerai, cucumber & brinjal

Ridge Gourd, Brinjal & cucumber 

Agathi Keerai, Brinjal, Kaaramani & Palak

Pests & Control Methods

Now there is growing demand for non-chemical means for controlling diseases, insects, and other pests. Allergic reactions to chemicals, a desire to grow purely organic vegetables, or protection for young children are all reasons to use non-chemical controls for pests. If used correctly, non-chemical pest controls can be very effective in keeping your garden healthy.

VFNT Seeds: The easiest way to avoid disease problems is to choose varieties of vegetables that are resistant to disease. Over the years, many disease-resistant vegetable varieties have been developed. You'll notice that seed packages and catalog descriptions of some vegetable varieties include V, F, N, and T in the name. These abbreviations indicate disease resistance that has been bred into the variety. V and F stand for verticillium and fusarium wilts, which are fungi that cause tomato plants to turn yellow, wilt, and die. N indicates nematode tolerance. Nematodes are tiny parasitic worms that cause knots on stems and roots of vegetables. Tobacco mosaic virus, indicated by a T, affects foliage by yellowing and curling; it also causes severe root damage.

Water Early: If you water your plants with a from overhead, it's best to water early in the day so plants can dry off before night falls. Foliage that stays wet for long periods of time is susceptible to leaf diseases, fungi that grow on leaves, tender stems, and flower buds. This tends to be a problem when plants stay wet throughout the night: Fungi spread quickly during the cool, moist evening hours. The fungi will cause the plant to be weakened, flowers will fall off, and fruit will begin to spot and become soft.

Crop Rotation: Do not grow the same plant family in the same spot year after year. Repetition of the same crop gives diseases a chance to build up strength. Design your plan so that each family of vegetables --cabbage family, cucumber family, and tomato/pepper family -- can be moved to another block of your garden on a three-year rotation.

Paper Collar

You may notice one morning that a couple of healthy young plants have keeled over and died. This is a pretty sure indication that cutworms are present. Feeding at night and hiding during the day, cutworms are most destructive early in the season, cutting off transplants at ground level. To prevent the cutworm from finding your cabbages, peppers, and tomatoes, wrap each stem with a paper or thin cardboard collar as you transplant it into the garden. The collar should reach at least one inch below and one inch above the soil level. In time, the collar will disintegrate; by then the danger of cutworm damage will have passed.

Beer: A Handy Bait

Snails and slugs pose a problem for many garden plants, especially during seasons with plenty of rain and rich, succulent growth. Lettuce and potatoes are especially susceptible to slug damage: Irregular holes will be found in the leaves. Snails and slugs feed mostly at night, hiding from the hot sun.

One way to control these pests is to remove the places where they hide; but if you're using mulch in the garden and supplying plants with the moisture they need, you're still likely to find snails and slugs. Although commercial baits are available, shallow pans of beer placed throughout the garden will attract and drown the pests.

Beneficial Insects

Not all insects in the garden are pests. Most are benign residents, and some are actually beneficial, providing a means to control insect pests. Insects such as ladybugs, lacewing flies, and praying mantises feed on bugs that are destructive to your crops. You should protect them when you find them in your garden. Harmless to your garden plants, these useful insects gorge on aphids, beetles, caterpillars, grasshoppers and other bothersome insects.

Sources : http://home.howstuffworks.com/organic-pest-control-for-a-vegetable-garden.htm

Changing Soil pH

Changing Soil pH to Match Plant Needs 

If your spinach is spindly and your tomatoes are troubled, changing soil pH may help. “pH” refers to potential hydrogen, or the hydrogen ion concentration of soil. pH is a measure of soil acidity.  

The pH scale ranges from 1 to 14. It’s a logarithmic scale, like the Richter scale to measure earthquakes. A soil with a pH of 6 is ten times more acidic than a soil with a pH of 7.  Neutral pH is 7.0. A soil with a pH lower than 7 is an acidic soil. A soil with pH higher than 7 is an alkaline soil. Soil acidity determines the availability of mineral nutrients for your vegetables. In alkaline soils, phosphorous, iron, and zinc are limited. In acidic soil, calcium and magnesium are less available to plants. 

  

Lowering Soil pH  |  Buffering Soil pH  |  Raising Soil pH 

  

Soil pH varies by up to half a point over the year. Soil pH tends to be higher (more alkaline) when the soil is cool, and lower (more acidic) in summer, when increased bacterial activity in warmer weather has an acidifying effect on soil. Factor this in when changing soil pH. Garden soil pH is usually neutral to slightly acidic, pH 6.5-7.0. This also happens to be the ideal soil pH for vegetables. 

However, if you want to really tweak performance: 

Green, leafy vegetables (like spinach and lettuce), cruciferous vegetables (like broccoli, cauliflower, cabbage, and kale), and other Winter Vegetables prefer a more alkaline soil, pH 7.0-7.2. 

Fruiting plants, like nightshades (tomatoes, peppers, eggplants) and cucurbits (cucumbers, melons, squash) prefer a more acidic soil, pH 6.0-6.8. See  Summer Vegetables for more information on the preferences of these summer favorites.  

Adding organic matter is an indirect method of soil pH adjustment. Organic matter “buffers” soil, especially sandy soil.  The higher the organic matter content of a soil, the more lime it takes to raise the soil pH 1 point, and the more sulfur it takes to lower the soil pH 1 point. 

Plants grown in soil with a lot of organic matter have healthier roots. They’re able to extract enough nutrients from the soil even when the pH isn’t optimal.  In a healthy soil with adequate organic matter, changing soil pH may not be necessary, because plants continue to grow at pH levels that would stunt growth in leaner soils.  

When you increase soil organic matter, you’re not really changing soil pH, you’re increasing your plants’ tolerance for acidic or alkaline conditions. For information on increasing soil organic matter, see how to improving Garden Soil. 

Lowering Soil pH 

Why would you want to lower soil pH?  

If soil pH testing indicates your soil is greater than 7.0, you have an alkaline soil, and changing soil pH may be called for, depending on what you’re growing.  As soil acidity increases, minerals like phosphorous, iron, and zinc become more available. 

In alkaline soils, these minerals—especially iron and zinc—are bound up and less available. Fruiting plants like tomatoes, peppers, squash, and melons need these minerals to flower and set fruit. Soil acidification also makes life more difficult for many weeds. Weeds are early successional plants that evolved in thin, alkaline soils. In acidic soils, many weeds are weaker competitors.  

Ways to Lower Soil pH (Make Soil Acidic) 

Soil pH can be lowered by half a point—from 7.0 to 6.5, for example—by increasing soil nitrogen. Adding compost, manure, or organic soil amendments like alfalfa meal to the soil can help drop pH over time by increasing bacterial populations.  

There's a myth that coffee grounds (2-0-0) are a quick fix for lowering soil pH. Most of the organic acids in coffee are water-soluble, and flush out into the brew. Coffee grounds have a pH around 6.8, close to neutral, so they won't do much to lower pH. They do add a little nitrogen, so they can help reduce pH over time, just like manure or compost.  

If you need to drop soil pH more quickly, try watering your plants with leftover (cold) coffee, diluted 50-50 with water. This works especially well for houseplants and container vegetables. To lower soil pH by larger amounts (more than half a point), use Elemental Sulfur, sometimes called “Flowers of Sulfur”.   

When using sulfur for changing soil pH, be aware that the acidifying effect depends on soil bacteria (thiobacillius), which oxidize the sulfur and release dilute sulfuric acid into the soil over a period of weeks to months.   

Because the acidifying effect of sulfur depends on soil bacteria: 

The sulfur must be dispersed through the soil to be in contact with these bacteria. Make sure you mix the sulfur thoroughly into the soil. Otherwise, there will be strongly acidic areas around blobs of sulfur, and no effect elsewhere in the soil.  

Sulfur only works during the summer, when the soil is warm and bacterial activity is at its highest. 

Sulfur is not a quick-fix for changing soil pH. After application there is a delay of several weeks to several months before soil bacteria break down the sulfur to acidify the soil. 

Elemental sulfur is acceptable as an organic soil amendment for changing soil pH under National Organic Program (NOP) guidelines. 

When using elemental sulphur for changing soil pH, it's best to divide the amount to be applied to achieve the desired drop into 2 or 3 applications over the entire season, instead of a single application. Applications should be 6-8 weeks apart. 

NOTE: Application amounts in the table below apply to loam soil. 2.4 lbs of elemental sulphur (per 100 square feet) will drop loam soil pH by 1 point. 

• For Clay Soil, INCREASE amounts by half (50%). 
• For Sandy Soil DECREASE amounts by one-third (33%). 

Present Soil pH	To pH 6.5	To pH 6.0	To pH 5.5	To pH 5.0	To pH 4.5
8.0	3.6 lbs	4.8 lbs	6.0 lbs	7.2 lbs	8.4 lbs
7.5	2.4 lbs	3.6 lbs	4.8 lbs	6.0 lbs	7.2 lbs
7.0	1.2 lbs	2.4 lbs	3.6 lbs	4.8 lbs	6.0 lbs
6.5	---	1.2 lbs	2.4 lbs	3.6 lbs	4.8 lbs
6.0	---	---	1.2 lbs	2.4 lbs	3.6 lbs

Pounds of Elemental Sulfur Needed for Reducing Soil pH  

(100 square feet of Soil 6” Deep, LOAM soil) 

NOTE : 1.2 lbs is around 543 gms. 

Raising Soil pH 

Why would you want to raise soil pH? 

If you’re growing fall or cool-season vegetables, these green, leafy vegetables perform better in soils with a slightly higher pH, between 6.8 and 7.5. 

Ways to Make Soil More Alkaline (Reduce Acidity) 

Dolomite Lime, (calcium magnesium carbonate), is the most common soil amendment for raising soil pH (reducing acidity). It’s used by both organic and conventional farmers, but should Not be used in soils with adequate or excess magnesium.  

Plants need magnesium in small amounts, and excess magnesium stunts and kills vegetables. Where a soil test indicates adequate or high magnesium levels, use an alternate calcium source for changing soil pH.  

The following table provides application rates according to soil textural type:  

Soil Texture Type	Raise pH 1 pt (4.5 to 5.5)	Raise pH 2 pts (5.5 to 6.5)
Sandy & Loamy Sand	2.3 lbs	2.75 lbs
Sandy Loam	3.6 lbs	5.9 lbs
Loam	5.5 lbs	7.8 lbs
Silt Loam	6.9 lbs	9.1 lbs
Clay Loam	8.7 lbs	10.5 lbs
Muck	17.4 lbs	19.7 lbs

Pounds of LIME Needed for Changing soil pH  

(100 square feet of Soil 7” Deep) 

NOTE : 1.2 lbs is around 543 gms. 

You can see the buffering effect of soil organic matter in the table above. As organic matter increases with each soil textural class, the amount of lime needed for changing soil pH increases significantly.  

The same thing happens when you’re lowering soil pH with sulfur. The heavier your soil, the more sulfur it takes to drop the pH 1 point.  

Clay and loam soils give you more wiggle room when changing soil pH. Sandy soils, not so much.  

Where dolomite lime may create magnesium toxicity, use any of the following alternative calcium sources instead:  

Ground Oyster Shell (1-2 lbs/ 100 sq ft) 

Dried, Crushed Eggshells (1-0.4-0), a kitchen byproduct, are a great source of calcium and a good method of changing soil pH to reduce acidity. (1-2 lbs/ 100 sq ft) 

Hardwood Ashes Short-term soil pH adjustment. (Use up to 1.5 lbs/ 100 sq ft.) 

Calcite (high-calcium lime). Use up to 1.5 lbs/ 100 sq ft. 

source : www.grow-it-organically.com