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Soils FAQ


Soils are a key enabling resource for human well-being, central to the creation of a host of products and essential ecosystem services:

• Soils are the basis for the production of food, fibers, fuel and medicinal products.

• Soils absorb, store, alter, purify and release water, both for plant growth and water supply.

• Soils interact with the atmosphere through absorption and emission of gases (e.g. carbon dioxide, methane, water vapour) and dust;

• Soils make up the greatest pool of terrestrial organic carbon (over double the organic carbon stored in vegetation).

• Soils regulate carbon, oxygen and plant nutrient cycles (N, P, K, Ca, Mg, etc.)

• Soil is the habitat of several animals and organisms such as bacteria and fungi and thus sustain biological activity, diversity and productivity.

• Soil is the habitat for seed dispersion and dissemination of the gene pool.

• Soils buffer, filter and moderate the hydrological cycle.

• Soils are the platform for urban settlement and are used as materials for construction

Yes, it is true. There are billions of microorganisms such as bacteria, fungi, and protozoans in the soil, as well as thousands of insects, mites and worms.
Soil is considered a non-renewable resource because it does not renew itself at a sufficient rate in the human time frame. Indeed, one centimeter of soil can take hundreds to thousands of years to form from parent rock.
Soils and soil organisms provide a multitude of ecosystem services, including waste breakdown, release of nutrients, enhancement of soil structure and biodegradation of pesticides and other chemicals; in addition, they act as a sink for greenhouse gas emissions and fight pests and soil-borne plant pathogens, benefiting human and animal health including digestion and immunity. It is therefore important to maintain the genetic and species diversity of soil organisms for the continued provision of these functions.
Sustainable management of soil resources contributes effectively to the mitigation of: 1) climate change through carbon sequestration and reduction of GHG emissions; and 2) desertification processes. It is imperative to promote sustainable soil management practices for climate change mitigation and adaptation, and resilience to changing weather patterns and extremes. Protection and management of organic carbon-rich soils and the identification of zones that are either highly vulnerable to degradation or poorly resilient is of particular concern.
There is a very direct link between soil health and human health as 95% of the food we consume comes from soils. Micronutrient malnutrition is a major factor affecting the health and wellbeing of people throughout the world, especially in developing countries. Over two billion people suffer from micronutrient deficiencies, in particular vitamin A, iodine, iron and zinc, among others. Current food systems are being increasingly challenged to provide adequate, safe, diversified and nutrient-rich food for all, that contribute to healthy diets. Food grown on nutrient-impoverished soils contributes to systemic human (protein-energy) malnutrition because of the lack of important micronutrients in the human diet such as iron, lithium, magnesium, zinc, copper and iodine. Soil health and its fertility have a direct influence on the nutrient content of food crops. The available levels of micronutrients in soils are a primary factor in determining micronutrient content of crops. If the necessary micronutrients are not present in the soil, this impacts directly on the food system by failing to deliver adequate amounts of micro¬nutrients to meet human requirements. This is especially true for trace elements that are essential nutrients for humans but are not known to be essential for plant growth, such as selenium and iodine. There is evidence about the relation between deficiencies of zinc, selenium and iodine in humans and related deficiencies of those microelements in soils. From a different angle, plants not only absorb nutrients and water from the soil but they also up-take other harmful substances present in a plant-available form in the soil solution such as heavy metals and pollutants, which can harm both humans and animals, and accumulate in the food chain.
Soil is where food begins! It is estimated that 95% of our food is directly and indirectly produced on our soils. Therefore, food availability relies on soils. Healthy and good quality food can only be produced if our soils are healthy. A healthy living soil is a crucial ally to food security and nutrition.
Soil degradation is the reduction in the capacity of soil to provide ecosystem goods and services and ensure its functions over a period of time for the beneficiaries of these. Soil degradation manifests itself in various forms, such as: soil erosion, soil salinization, nutrient depletion, loss of soil biodiversity, soil pollution, soil compaction, loss organic matter, soil sealing and others.
Studies report that approximately 33% of our soils are facing moderate to severe degradation. The current rate of soil degradation threatens the capacity to meet the needs of future generations, unless we reverse this trend through a concerted effort towards the sustainable management of soils.
Soils provide a key set of fundamental ecosystem services that are crucial for our well-being. Despite their crucial role, soils have been taken for granted for a long time. Considering that human pressures on soils are reaching critical limits that jeopardize our future, there is an urgent need to raise awareness on the importance of this strategic resource.
To protect the planet’s soil resources, it is important to:

• Prevent and reverse soil degradation

• Practice sustainable soil management

• Prevent soil pollution

• Avoid sealing the soil

• Combat climate change

• Shrink your carbon footprint

• Preserve and increase vegetation cover

• Stop food waste

• Spread the word about the importance of soils


Soil contamination implies that the concentration of a substance (e.g. nutrient, pesticide, organic chemical, acidic or saline compound, or trace elements) in soil is higher than would naturally occur (See also soil pollution).
Soil pollution refers to the presence of substances at concentrations above threshold levels where they become harmful to living organisms (See also soil contamination). Soils break down pollutants and limit groundwater and surface water pollution. Indeed, soils hamper pollutants leaching into the groundwater and limit their transport to surface waters.
Send your soils samples to a soil laboratory.

• Build raised beds.

• Use soil amendments to stabilize contaminants in soil. Adding a thick layer of organic matter to your soil provides a physical barrier to contamination. Soil amendments have also been used to bind contaminants so that they are no longer mobile or bioavailable. Soil amendments improve the overall soil quality for growing plants and are a good addition to any soil.

• Remove all contaminated soil and replace it with clean soil. Make sure the replacement soil is clean by asking the supplier for proof that the soil that was tested to be contaminant-free.

Plants that produce fruiting bodies (tomatoes, squash, apple and pear trees, and tall berries) are most appropriate for growing in potentially contaminated soil. Root and tuber crops (carrots, potatoes and radish) are often the least appropriate plants to grow in potentially contaminated soil, as the edible portions of the crops are in direct contact with the soil. Vegetables with large outer leaves (cabbage, lettuce and collard greens) and herbs (mint, sage, thyme) are easily contaminated by dust and soil splash back, so careful washing of these plants is necessary.

1. Use clean soil and compost. If you are concerned about contamination in your garden soil, consider having it tested by a New York State-certified laboratory.

2. Use raised beds.

3. Build beds deep enough for the roots of your crops, and maintain them by adding compost often.

4. Avoid treated wood.

5. Railroad ties, telephone poles, pressure-treated wood and some painted wood contain chemicals that can get into soil.

6. Maintain soil nutrients and pH. Healthy garden soils have a good nutrient balance and a pH near neutral (6.5 – 7).

7. Cover (or mulch) soil.

8. Use compost, straw or bark mulch in garden beds, and stones or wood chips in paths and non-growing areas. This helps reduce soil splash, dust and tracking of soil home.

9. Keep an eye on children.

10. Make sure children do not eat soil or put dirty toys or other objects in their mouths. Young children can be more sensitive to certain chemicals in soil, such as lead.

11. Leave the soil in the garden. Avoid bringing garden soil into your home. Remove soil from garden tools and harvested vegetables while at the garden, and change your shoes before going indoors.

12. Wash your hands.

13. Wash up after gardening, and have children who play or work in the garden do the same. Consider wearing gloves, and remember to remove them when leaving the garden.

14. Wash and/or peel produce. Wash vegetables thoroughly –especially leafy and root crops, which are more likely to have soil on them. Consider peeling if appropriate.

15. Put a barrier under play areas. Separate children’s play areas from underlying soil with landscape fabric or other durable material. Put clean play materials such as sand or wood chips on top. Check the barrier over time to be sure underlying soil isn’t mixing with play materials.

SOILS: PHYSICAL PROPERTIES (Formation & Processes)

As a dynamic natural system, soils are made up of the following components: inorganic mineral particles (sand, silt and clay, gravel, stones and rock), organic matter, air, water and living organisms. The specific contribution of these different components to the soil system has a prominent effect on soil functions and depends on soil type, and its related forming factors. Man-made materials may also form part of the soil.
There are many different factors that come together to create soils, and the process can take thousands of years to reach an equilibrium. The main soil forming factors are: climate, topography, parent material, time and biological factors (plants, animals, micro-organisms and humans). Different combinations and intensities of soil forming factors lead to different soil types.
Soils support plant growth by providing anchorage, sufficient oxygen, moisture and nutrients. Additionally, soil protects roots from drastic fluctuations in temperature by buffering temperature modification.
Nutrients in soil are recycled through the decomposition of organic matter coming from plant or animal sources. Soil microorganisms break down the organic matter and make the nutrients available to living organisms.
The ability of a soil to store water is called soil water retention capacity and it is related to the particle-size distribution. The particle-size distribution is also related to the ability of a soil to act as a filter. Indeed, the finer the soil particles, the higher the ability of the soil to trap pollutants and prevent them from leaching into the groundwater.


Soil health is the capacity of soil to function as a living system. Healthy soils maintain a diverse community of soil organisms that help to control plant disease, insect and weed pests, and form beneficial symbiotic associations with plant roots. Healthy soils recycle essential plant nutrients, improve soil structure with positive repercussions for soil water and nutrient holding capacity, and ultimately improve crop production. A healthy soil does not pollute the environment; rather, it contributes to mitigate climate change by maintaining or increasing its organic carbon content.

1. Good soil tilth

2. Sufficient depth

3. Sufficient but not excess supply of nutrients

4. Small population of plant pathogens and insect pests

5. Good soil drainage

6. Large population of beneficial organism

7. Low weed pressure

8. Free of chemicals and toxins that may harm the crop

9. Resistance to degradation

10. Resilience when unfavorable conditions occur

Soil pH generally refers to the degree of soil acidity or alkalinity. Chemically, it is defined as the log10 hydrogen ions (H+) in the soil solution. The pH scale ranges from 0 to 14; a pH of 7 is considered neutral. If pH values are greater than 7, the solution is considered basic or alkaline; if they are below 7, the solution is acidic. It is important to recognize that because the pH scale is in logarithmic units, a change of just a few pH units can induce significant changes in the chemical environment and sensitive biological processes. For example, a soil with pH 5 is 10 or 100 times more acidic than a soil with pH 6 or 7, respectively. Soil pH affects the soil's physical, chemical, and biological properties and processes, as well as plant growth. The nutrition, growth, and yields of most crops decrease where pH is low and increase as pH rises to an optimum level.
Soil organic matter (OM) is the portion of soil that includes plant and animal remains in various stages of decay, and soil microbes.

Functions of OM:

• Nutrient and water storage. Humus particles are small (colloids), have a large surface area

• Nutrient availability – humus releases nutrients

• Soil aggregation – organic matter causes soil particles to clump together to form aggregates. Better aggregation improves soil tilth and permeability, aeration, water absorption

• Preventing erosion –more water infiltrates in organic rich soils and less water runs off

Roots by themselves provide diversity. Fibrous roots reduce bulk density, tap roots loosen compaction, deep roots uptake or scavenge N, P, and other nutrients. Also, the rhizosphere (area around roots) are areas highest of concentration for soil life. Roots release exudates and soil life feeds off these proteins and sugars.
Tilth generally refers to the physical condition of the soil as it relates to plant growth. Favorable tilth implies good conditions for seed germination and root proliferation, allowing crops to thrive. Also, a soil with good tilth facilitates other processes, such as water infiltration and aeration, which benefit both crop and environment. Good soil tilth is usually equated with aggregation (presence of soil crumbs), because stable aggregates promote these favorable processes. Crop rotations can have a positive impact on soil tilth, depending on the crops that are being alternated. Additional ways to improve soil tilth include reducing tillage and using cover crops. There are thus a number of approaches to improving the physical quality of the soil, and often a combined approach produces the greatest improvement.


Here are some keys to improving soil health:

• Add Organic Matter (compost) consistently

• Decrease/lessen Disturbance

• Increase Cover Crops

• Increase Biodiversity

• Have living roots all year

Dig down to the depth of a root system (~1 foot). Add a few inches of compost and thoroughly mix.
Add 3-5 inches of mulch to your bed. Make sure you have a good mix of real soil (sand, silt and clay) and organic matter.
Making a Bottle Drip System. Make sure that the soil is completely damp. If the soil is too dry, it will soak up all the water from your bottle before you even leave for your trip. Get a plastic, 2-liter (2-quart) bottle. If you have a smaller plant to take care of, a smaller bottle will do just fine. Since you will be burying this bottle in the soil, this method will work best for garden plants or plants in large containers. Use a hammer and nail to poke 2 holes into the bottom of the bottle. Poke a few more holes up the sides of the bottle. Dig a hole in the dirt next to your plant. Insert the bottle into the hole. Fill the bottle with water.
If your soil pH test results came out to be acidic, add lime powder to bring pH up.
Tillage breaks down soil aggregates resulting in destruction of soil structure. Soil structure provides channels and macro pores that allow water, air, and root movement. When structure is destroyed, compacted zones form restricting air, water, and root penetration. Tillage can be used to remove the zone of compaction temporarily. The long-term solution is to plant cover crops to increase organic matter, soil organisms, and aggregate stability, thus improving soil structure. Fibrous roots of cover crops such as cereal rye will reduce soil bulk density. Brassicas, with deep tap roots, will loosen the soil. As soil organisms increase, they will continue to aggregate the soil and form bio-pores and channels. As soil health improves, the soil is more resilient to soil compaction.
Increasing soil cover leads to increase of active soil organic matter as soil microbes begin to break down organic material. Also, maintaining good cover on soil surface protects break down of soil aggregates that leads to soil erosion.

• Place a layer of landscape fabric on top of the ground soil before adding the clean soil and organic matter. The fabric layer creates a barrier beneath the soil in the bed that prevents plant roots from entering the ground soil below the bed.

• Build a frame to hold the clean soil for a permanent raised bed. Ask for non-treated lumber when getting wood to build the frame.

It depends on a lot of factors: what crop are you following, what crop are you planning to plant after the cover crop, do you need more soil cover, a nitrogen fixer, a nitrogen scavenger, to mitigate soil compaction, lots to think about (plan).
It depends on soil type and primary crops you produce. Hairy vetch is an excellent legume adapted to about every soil type and drainage group but most wheat producers don’t want it because it can be invasive in small grain crops. Crimson clover is the most common cover crop planted. Other choices include: Austrian winter peas, red clover, sweet clover, tropical sun hemp, cowpeas, soybeans and other legumes.
Plant diversity is one of the pillars of soil health. Diversity provides different rooting structures, and different root exudates (sugars) that feed a diversity of soil biology. Plant diversity can increase biomass produced and help insure against cover crop failure. The mix should not contain too high of a rate of early growth species like brassicas or they can smother the rest of the species.
There are benefits to planting cool and warm season cover crop species together but don’t plant too high of a rate of a warm season going into the cool season or too high a rate of a cool season species going into the warm season. Typically, 20% or less is enough of the cover crop planted at the end of its normal growing season. Planting date is important too, with a cool season planting you don’t want more than 60 days growth of the warm season prior to the first frost.
Earthworms are a very important ally in improving soil health. They improve aeration and water infiltration by developing macropores, channels for water and air movement and they improve aggregate stability. Earthworm castings are five to six times more fertile than surrounding soil.
Living roots and biomass (crop residue) on the soil surface feeds soil life. Interestingly the earthworm is a farmer, they pull residue underground to feed bacteria which are then eaten by protozoa. The earthworm then consumes the bacteria. Reducing tillage and disturbance preserves their habitat and their benefits

• The first step is to stop watering the yard so much. Soil that is dried out will become less hospitable for worms.

• Earthworm removal can be easily done by using an electrical device. These earthworm removal probes send a mild electrical current down into the soil. The current drives the worms up to the surface of the soil.

Carbon to Nitrogen ratio. Plants like brassicas and legumes have a lower C:N ratio. Greater than 25:1 increases residue on the surface whereas C:N ratio’s below 25:1 mineralize fast and decrease surface residue.


Soil organic matter (OM) is the portion of soil that includes plant and animal remains in various stages of decay, and soil microbes. Functions of OM:

• Nutrient and water storage. Humus particles are small (colloids), have a large surface area

• Nutrient availability – humus releases nutrients

• Soil aggregation – organic matter causes soil particles to clump together to form aggregates. Better aggregation improves soil tilth and permeability, aeration, water absorption

• Preventing erosion –more water infiltrates in organic rich soils and less water runs off

Fertilizers enrich soils content of micro- and macronutrients. However, overuse of fertilizers can result in soil and water contamination. We recommend using organic matter (compost), beneficial microbes and/or certified organic products as an alternative to commercial fertilizers, pesticides and herbicides.
Search for products using the Organic Materials Review Institute (OMRI) list. OMRI is a 501(c)(3) nonprofit organization providing organic certifiers, growers, manufacturers, and suppliers an independent review of products intended for use in certified organic production, handling, and processing. OMRI reviews input products to determine compliance with the USDA National Organic standards and/or Canada Organic Regime (COR) standards. Inputs include products such as fertilizers and pest control products for crop production, livestock feed ingredients and health care products, processing aids and sanitizers, and other materials intended for use in organic production. WEBSITE: What Can I Compost? YES

• Fruit and vegetable scraps

• Coffee grounds, filters, and paper tea bags

• Bread and grains

• Egg and nut shells

• Food-soiled paper towels and napkins

• Shredded newspaper

• Sawdust and wood shavings from untreated wood

• Stale beans, flour, and spices

• Cut or dried flowers

• Houseplants and potting soil

• Feathers


• Meat or fish scraps

• Cheese or dairy products

• Fats, grease, oil, or oily foods

• Cat or dog feces

• Kitty litter

• Colored or glossy paper

• Sawdust made from pressure-treated plywood or lumber

• Coal or charcoal ashes

• Non-compostable materials like plastic, metals, or glass

• Diseased or insect-infested houseplants and soil

• Biodegradable or compostable plastics

Make your own compost or get free compost from city organizations, e.g. NYC Compost Project


• Seasonal Deliveries

• Community gardeners, street tree stewards, parks, and other nonprofit organizations can request free pallets of bagged compost. Check for updates on seasonal distribution schedule.

Check back for updates on upcoming DSNY Compost Giveback Events and connect with us to stay updated on all our programs and events.
The NYC Compost Project creates compost from materials accepted at food scrap drop-off sites throughout New York City. The compost is donated to local greening initiatives to rebuild NYC’s soils. Contact the NYC Compost Project and Big Reuse for more information. Attend a Turn & Learn Volunteer Workday at the NYC Compost Project Hosted by Snug Harbor Cultural Center & Botanical Garden on Staten Island. Please note this is a volunteer event and not a pick-up event; you must volunteer at the workday to receive compost. Supplies may be limited. Registration is strongly recommended.
Registered commercial landscapers can purchase bulk compost from the Staten Island Compost Facility. Find out how to register. The NYC Compost Project, created by the NYC Department of Sanitation (DSNY) in 1993, works to rebuild NYC’s soils by providing New Yorkers with the knowledge, skills, and opportunities they need to make and use compost locally. NYC Compost Project programs are implemented by DSNY-funded teams at seven host organizations, including Brooklyn Botanic Garden, Big Reuse, Earth Matter NY, Lower East Side Ecology Center, Queens Botanical Garden, Snug Harbor Cultural Center & Botanical Garden, and The New York Botanical Garden.


You should water a little less often so the top inch or two of soil is allowed to go dry.
The Cabbage white butterflies lay their eggs on the underside of leaves of plants in the cabbage family. The larvae will feed on the leaves eventually pupating into butterflies. The adult butterflies are pollinators of dandelion, strawberries, mint, and loosestrife.
You can start perennial herbs from seed. They will just take longer to grow and will take a couple years before they will be well established. If you are looking for a quicker solution to growing your herbs, you can buy an already established plant.
The best time to plant tomatoes is mid to late may when there is no fear of frost in the forecast. These plants love the hot summer weather so planting them before this time will not be beneficial to your garden and future tomato crop.
They will crack if they are getting too much water either from rain or watering.
The reason they fall off is due to Tomato Blossom Rot which is a virus. This is not really worth treating. Plant should be removed and thrown away. Do not compost in your bin to spread to other plants in the future.
By planting more native perennial, you will attract more pollinators to your garden. In doing so, they will pollinate your veggies.
Hand weeding weekly is the best way to control weeds. Be sure to pull the complete root with the plant.
There are a variety of fertilizers, choose the best one for your needs making sure it is all organic. A few good ones are Neptune’s Harvest Seaweed Fertilizer and Alaska Fish Emulsion.
There are Safer Soaps available (look for organic ones) that will help control aphids. A natural way to get rid of aphids is by removing the most populated leaves and introducing lady bugs to the garden as a natural predator to the aphids.
Squash plants will produce white blotches on their leaves as part of natural leaf coloration. However, powdery mildew fungus can also turn leaves white and powdery. A good way to avoid this is to water first thing in the morning so water does not set on leaves overnight.
It is called tomato mosaic virus otherwise known as blight. The virus is soil borne, removing lower branches/leaves and mulching around the plants will help minimize infection. Also, note, tomatoes with blight should not be composted in normal compost bins to avoid spreading infection.
The greens store best in a plastic bag in the refrigerator. They can last up to a couple of weeks stored in this way.
Please remove cat poop as you see it but as long as you are washing all your veggies before you consume them it ok to eat these veggies.
Try filling the rat holes but contact who is in charge of the garden and another measure may need to be taken to get rid of these creatures.
Yes, bees are one of nature's most important pollinators. They will not harm you or anyone as long as you don’t bother them.
Put a shallow dish of sweet liquid or beer around the garden that will attract the slugs and then drown them thus ending the harm to your plants. Also, you could surround your garden edge with Diatomaceous Earth
Bananas would be treated as an annual in the garden. It is used more in this region as an ornamental plant and can survive the winter depending on the severity of it, but it will not fruit here.
Yes, but it probably will not taste very good. Once the plant has gone to see all its energy goes toward producing that seed. The leaves that are left taste bitter and often become rigid.
You should remove the spent plant material for winter and plant a cover crop such as winter rye or vetch. This will allow the crop to grow and put nutrients in the soil over the winter for the next season. Also, this will help protect the soil from blowing around in the winter wind and keep it intact for the next year.
Any veggies that have a harvest date up to 60 days can be planted in the fall. Different kinds of lettuce, radishes, snap peas and leafy greens can work well during the fall.
August and April.
Everyday especially when the weather is at its hottest.
Plants should be rotated every season. It is good to keep a map or garden journal to keep track.
With limited space, you can plant closer, but the plants will need a little space for proper air circulation. Without this air circulation, plants are susceptible to insects and certain diseases that will inhibit their growth.

Plaster, Edward. Soil Science and Management, Cengage Textbook. 
Weil, Raymond R.; Brady, Nyle C., Emeritus Professor. Nature and Properties of Soils, The. Pearson Education. orders/,