Soil: The Incredible Resource Below Our Feet

No garden can be successful without healthy soil. Often mistakenly undervalued, soil is the fundamental resource sustaining everything on earth. Plant life and the organisms that depend on plants could not survive without it. It is a living thing with many parts systematically working together. Soil provides the minerals, nutrients, biological elements, and the structure plants need to grow and thrive. But, don’t confuse soil with dirt. Dirt refers to bits of debris that are unclean or dusty. Dirt cannot support plants, whereas soil is teaming with beneficial life.

Soils start as stones that have been broken down again and again over millennia by wind and water.  Those become particles of varying size (sand, silt, and clay). Among these particles is organic matter, decaying plants, animals, and microorganisms like bacteria and fungi. Soil has pore spaces that fill with air and water.  

“In just one teaspoon of agricultural soil there can be

one hundred million to one billion bacteria,

six to nine feet of fungal strands put end to end,

several thousand flagellates and amoeba,

one to several hundred ciliates,

hundreds of nematodes,
 up to one hundred tiny soil insects,

and five or more earthworms.”

(Penn State Extension, “Soil Quality Information”, 2012.)

What are the characteristics of quality soil?

As gardeners, managing soil can be just as important as managing the plants that grow in it. Soil should do what we want it to do. Whether you are growing a vegetable crop, ornamental shrubs, or a lush lawn, paying attention to your soil’s composition and fertility is vital.

The characteristics of soil are unique.  Ideally, soil should have lots of organic matter, the capacity to hold water and air, and the ability to release nutrients to plants. It also functions to anchor plants, insulate their roots, and resist erosion.

Soil in the home garden.
Photo Credit: Alyson Ricketts, Burlington County Master Gardener

Soil can be categorized by its texture; sand, silt, clay, or loam. Sandy soil provides good drainage to plants as it lets water freely pass through, although it does not hold many nutrients. Silt particles are smoother and silkier than sand. Clay is smaller particles and holds on to water and nutrients, but can be difficult for plants roots to move through. Loam soil contains lots of organic matter and is a combination of sand, silt, and clay.

The composition of your soil depends on your location. Although soils vary widely across the state, New Jersey has a designated state soil found mostly in southern locations.  Called “Downer” soils, they are loamy, acidic, and made of coastal plain sediments. These soils are good for growing agricultural crops and sustaining many species of woodland trees. 

How do you know what is in your soil?

Thinking about soil first is an important step. Knowing the characteristics of your soil will determine your approach to planting and can help you decide what to plant and where. Some soils are ideal for specific plants and not for others. Getting your soil tested is the only way to know what’s in there. You want to know if your soil has issues that need to be corrected or if any amendments are needed.  Getting a soil test is environmentally friendly because you won’t be adding any unnecessary fertilizers that have the potential to run off and contaminate waterways. Soil tests can save money because you won’t be buying amendments you don’t need.

Rutgers Soil Testing Laboratory

Photo Credit: Rutgers New Jersey Agricultural Experiment Station

Fall is a great time to have your soil tested so you can prepare before the growing season. The first step in getting your soil tested is to purchase a test kit from the Rutgers Cooperative Extension county office or follow the sampling instructions on the website. Make sure to follow the sampling instructions carefully.  About two cups of sample soil is required from several holes, dug about 6 to 8 inches deep. Also, you will need to submit a soil questionnaire. Areas used for different types of plants should be tested separately. For example, perennial beds should be tested separately from the lawn and separately from the vegetable garden. The report will arrive in a few weeks from the time of submission by email or mail. For questions about your soil report contact the extension office.

Rutgers Soil Testing Laboratory
https://njaes.rutgers.edu/soil-testing-lab/

The soil testing lab provides testing and reports to help
New Jersey residents achieve their agricultural and environmental goals.

Soil pH

Knowing your soil pH (how acidic or alkaline) is important because plants can’t take up the nutrients they require if the pH is not within the optimal range. If the soil pH is not correct for the plant, soil amendments can be used to adjust the pH. The soil test report will indicate if limestone should be used to raise the pH or a sulfur application is needed to lower pH.  A pH of about 6.5 is optimum for most plants. Some plants have special needs, however. Blueberries, for example, prefer to grow in very acidic soil with a pH between 4.0 and 4.8.

Macronutrients and Micronutrients

Soil already has nutrients in it. A soil test will tell you what nutrients and how much it contains. Macronutrients are required by plants in larger amounts than micronutrients. Macronutrients are nitrogen (N), phosphorus (P), and potassium (K). Micronutrients are calcium, manganese, boron, zinc, and copper. Depending on the levels, composted organic matter or specific fertilizers may be needed. If applying fertilizer, use the correct type and amount. Always read the label and instructions. 

How to Care for and Maintain Soil

Keeping your soil covered with mulch, compost or a cover crop is an important step. This will help with erosion control and also add nutrients as the cover decomposes. Covering soil will help minimize weeds, retain moisture, and moderate the temperature. Try to avoid walking on soil and instead stick to walkways. Compacted soil becomes a problem because roots, water, and air cannot move through it. This is why tilling, which can compact soil, should be done in moderation. Try to avoid disturbing soil as this can bring weed seeds to the surface to germinate. Finally, use an Integrated Pest Management strategy to avoid overuse of pesticides which can kill some of the living organisms in the soil.

Additional Resources:

Rutgers Publications Fact Sheet 719: “Soil Fertility Test Interpretation”
https://njaes.rutgers.edu/pubs/publication.php?pid=FS719

Rutgers Publications Fact Sheet 797: “Soil Testing for Home Lawns and Gardens”
https://njaes.rutgers.edu/fs797/

Penn State Extension: “Soil Quality Information”
https://extension.psu.edu/soil-quality-information

Rutgers Publications Fact Sheet 1135: Soil Organic Matter
https://njaes.rutgers.edu/pubs/publication.php?pid=FS1135

New Jersey Agricultural Experiment Station: “How to Have Your Soil Tested”
https://njaes.rutgers.edu/soil-testing-lab/how-to.php

Jersey Friendly Yards: “Step 2, Start With Healthy Soil”
https://www.jerseyyards.org/create-a-jersey-friendly-yard/8-steps/step-2-start-with-healthy-soil/

Soil Science Society of America: “Soils are Living”
https://www.soils.org/files/sssa/iys/july-soils-overview.pdf

USDA Natural Resources Conservation Service: “New Jersey Soil”
https://www.nrcs.usda.gov/conservation-basics/conservation-by-state/new-jersey/new-jersey-soils

Soil Science Society of America: “Downer, New Jersey State Soil”
https://www.soils4teachers.org/files/s4t/k12outreach/nj-state-soil-booklet.pdf

Michigan State University Extension: “Soil…it’s more than dirt”
https://www.canr.msu.edu/news/soilits_more_than_dirt

Rutgers University Extension: “Digging Deeper: What’s Your Soil Telling You?”
Video: https://www.youtube.com/watch?v=O0rNVblU_08

 Brooklyn Botanic Garden: “How Compost Builds the Soil”
https://www.bbg.org/article/how_compost_builds_the_soil#:~:text=Feed%20the%20soil%2C%20not%20the,Bin%20A%20homemade%20compost%20bin.

 

Some Tips on Planning a Vegetable Garden

 

We are in the middle of winter and winter is the best time to plan for your summer garden.  New and experienced gardeners can achieve great results by following some basic recommendations.  Here are some suggestions and resources that will guide you as you begin this year's gardening adventure.

Planning

Plan the garden on paper.  

Draw a map of the garden layout showing the location and spacing of the crops.  When planting, group tall crops (okraand sunflowers) and trellised vines (peas and beans) together on the north side of the garden so they won’t shade shorter plants.

One of the most important reasons to draw out a plan is so that you can use it in subsequent years to make sure you are rotating your crops as you should.  Vegetable crops in the same plant family should not be planted in the same area of a garden year after year.   See the table below for a list of common plant families.

Make a list of the plants that you enjoy eating and rank them in order of preference.

Keep a journal and record your thoughts and observations throughout the growing seasons.  The journal can be your reference point for what worked and what didn't work.  

Site Selection

Selecting a site for your garden:

• The site should have good drainage.  Avoid putting the garden in an area where rain water accumulates. 
• Easy access to water is essential.
• Proximity to your house.  Choose a location that is easy to get to and convenient. 
• Choose a location with a southern exposure where the plants will get plenty of sun.  Most vegetables need eight hours of direct sunlight
• The garden should be as small as possible to reduce the amount of unnecessary work.

Garden Format

If you don’t have space for a vegetable garden or if your present site is too small, consider raising fresh, homegrown vegetables in containers. A window sill, patio, balcony, or doorstep can provide sufficient space for a productive container garden. 

Container Garden - University of Maryland Extension

Some suggestions for choosing containers:

• Everyday objects can be recycled and used as containers.
• Avoid dark colored containers, since they create more heat that may damage a young plant's roots.
• Containers made of materials like clay dry out more quickly than containers made of plastic or metal.
• Containers should have holes for draining water, unless they are self-watering.
• Plastics not made for outdoor can become brittle.

Listed below are some recommendations for growing vegetables in containers.

Information for Growing Vegetables in Containers

Vegetable* Light Requirement**	Minimum Container Size	Distance (inches) Between Plants in Containers	Days from Seed to Harvest	Comments
Beans, bush FS	2 gal.	2-3	45-60	Several plantings, two-week intervals
Beets FS/PS	1/2 gal.	2-3	50-60	Thin plants when 6 to 8 inches tall
Carrots FS/PS	1 qt.	2-3	65-80	Several plantings, two-week intervals
Cabbage FS/PS	5 gal.	12-18	65-120	Requires fertile soil
Chard, Swiss FS/PS	1/2 gal.	4-6	30-40	Harvest leaves for long yield
Cucumbers FS	5 gal.	14-18	70-80	Require hot weather, vining types need support
Eggplant FS	5 gal.	1 plant per container	75-100	Requires fertile soil
Kale FS/PS	5 gal.	10-15	55-65	Harvest leaves
Lettuce, leaf PS	1/2 gal.	4-6	30-35	Harvest leaves
Mustard greens PS	1/2 gal.	4-5	35-40	Several plantings, two-week intervals
Onions, green FS/PS	1/2 gal.	2-3	70-100	Require lots of moisture
Peppers, Bell FS	2 gal.	1 plant per container	110-120	Require hot weather
Radishes FS/PS	1 pint	1	25-35	Several plantings, weekly intervals
Squash, summer FS	5 gal.	1 plant per container	50-60	Plant only bush type
Tomatoes FS	5 gal.	1 plant per container	55-100	Stake and prune or cage
Tomatoes, cherry FS	1 gal.	1 plant per container	55-100	Helps to stake and prune
Turnips FS/PS	3 gal.	2-3	30-60	Harvest leaves and roots

 

If you are not growing plants in a container the table below provides useful information for growing vegetables in New Jersey.

 

New Jersey Vegetable Planting Guide

Vegetable	Spacing (in.)		Transplant or Seeds	Planting Dates*	Avg. Yield per 10 ft. of Row
	In Row	Btwn. Rows
Asparagus	18	60	Crowns	Perennial	5 lb.
Beans, Lima, bush	4	24	seed	Ma,Ju,Jl	6 lb.
Beans, Lima, pole	36	36	seed	Ma,Ju,Jl	7 lb.
Beans, Snap, bush	4	24	seed	Ma,Ju,Jl	6 lb.
Beans, snap., pole	36	24	seed	Ma,Ju,Jl	7 lb.
Beets	3	15	seed	Ap,Ma,Ju,Jl	14 lb.
Broccoli	15	30	transplant	Ap,Ma,Jl,Au	8 heads
Brussels Sprouts	18	30	transplant	Jl	5 lb.
Cabbage	18	24	transplant	Ap,Jl	7 heads
Cabbage, Chinese	12	18	seed or trp.	Ap,Jl	10 heads
Carrots	3	15	seed	Ap,Ma,Ju,Jl	10 lb.
Cauliflower	24	30	transplant	Jl	5 heads
Celery	6	18	transplant	Ma,Ju	20 stalks
Chard, Swiss	6	24	seed	Ap,Ma,Ju,Jl,Au	20 plants
Collards	18	24	seed	Ap,Ma,Ju,Jl	10 lb.
Corn, Sweet	12	24	seed	Ma,Ju	10 ears
Cucumbers	36	30	seed or trp.	Ju,Jl	8 lb.
Eggplant	30	30	transplant	Ma,Ju	20 fruit
Endive	12	18	seed or trp.	Ap,Ma,Ju,Jl,Au	10 plants
Kale	15	18	seed	Jl,Au	24 lb.
Kohlrabi	4	15	seed or trp.	Ap,Ma,Jl,Au	20 bulb.
Leeks	3	15	transplants	Ap,Ma,Au	40 plants
Lettuce,Leaf,Romaine	8	15	seed or trp.	Ap,Ma,Au,Se	15 heads
Lettuce, Bibb	6	15	seed or trp.	Ap,Ma,Au,Se	20 heads
Muskmelons	36	72	seed or trp.	Ju	8 melons
Mustard Greens	12	15	seed	Au	10 lb.
Okra	24	36	seed	Ma,Ju	100 pods
Onions, dry	4	15	seed,trp.sets	Ap	10 lb.
Parsley	6	15	seed	Ap,Ma,Ju	20 bunches
Parsnips	3	18	seed	Ap	10 lb.
Peas	2	18	seed	Mr,Ap	3 lb.
Peppers	15	15	transplant	Ju	12 lb.
Pumpkins	48	96	seed	Ju	4 fruit
Radishes	1	12	seed	Ap,Ma,Ju,Jl,Au,Se	60 roots
Rhubarb	36	48	crowns	Perennial	20 stalks
Rutabagas	4	18	seeds	Ap,Jl	15 lb.
Spinach	4	18	seeds	Ap,Se	7 lb.
Squash, bush	24	48	seeds or trp.	Ju,Jl	25 fruit
Squash, vine	36	72	seeds or trp.	Ju	20 fruits
Sweet Potatoes	12	36	transplants	Ju	12 lb.
Tomatoes	24	36	transplants	Ma,Ju	50 lb.
Turnips	3	18	seed	Ap,Jl	7 lb.
Watermelons	36	96	seed	Ju	3 melons
White Potatoes	12	24	tubers	Ap	18 lb.

*Mr=March; Ap=April; Ma=May; Ju=June; Jl=July; Au=August; Se=September

Many new vegetable varieties of vegetables are constantly being developed.  Before purchasing vegetable plants read the label carefully,  note the growing conditions, date to maturity, resistance to disease and pests.

Some common vegetables and their plant family classifications.

PLANT FAMILY	VEGETABLE
Carrot Family (Apiaceae)	carrot, celery, parsley, parsnip
Goosefoot Family (Chenopodiaceae)	beet, spinach, Swiss chard
Gourd Family (Cucurbitaceae)	cucumber, muskmelon, pumpkin, summer squash, watermelon, winter squash
Grass Family (Poaceae)	ornamental carn, popcorn, sweet corn
Mallow Family (Malvaceae)	okra
Mustard Family (Brassicaceae)	broccoli, Burssels sprouts, cabbage, cauliflower, Chinese cabbage, collard, kale, kohlrabi, mustard greens, radish, rutabaga, turnip
Nightshade Family (Solanaceae)	eggplant, pepper, potato, tomato
Onion Family (Alliaceae)	chives, garlic, leek, onion
Pea Family (Fabaceae)	bush bean, kidney bean, lima bean, pea, pole bean, soybean
Sunflower Family (Asteraceae)	endive, lettuce, sunflower

Test and Prepare the Soil

Example of a soil test kit

Soil testing is an easy, quick and accurate method to determine the relative acidity of the soil. The test will also measure the level of some essential nutrients (phosphorus, potassium, calcium, magnesium, sodium, sulfur, manganese, copper, and zinc) needed for healthy plant growth. Samples for planting and gardening projects should be submitted several weeks before you plan to plant. This will allow plenty of time for you to get the results back and if necessary, amend the soil before planting.  The results from the test will aid you in plant selection, soil preparation, and fertilization. The test results will help you avoid overfertilization, which can stimulate excessive plant growth and increase the likelihood of some diseases. Applying the correct grade and amount of fertilizer can also help reduce pollution of our water supplies and allow you to have healthier, more productive plants.

Irrigation

Generally speaking, most vegetable crops grow best if they receive about an inch of rainfall per week through the growing season. In a season with regular rainfall, supplemental irrigation may not be necessary except when first transplanting young plants into the garden. However, in a dry year, access to irrigation may be needed. Many gardeners irrigate overhead (with a hose and nozzle attachment or with a sprinkler system) or using drip irrigation (using soaker hoses).   Drip irrigation is the most efficient method for irrigation.  In drip irrigation systems the water is slowly released at the garden's surface through plastic tubing with tiny holes.  Reliable and convenient access to a source of water is critical to the success of your garden.

Integrated Pest Management (IPM)

IPM is method that can be used to manage weeds and other pest in a garden.  What is IPM?  IPM is a "science-based decision-making process that combines tools and strategies to identify and manage pests".  In a garden, a pest is any organism (plant or animal) that interferes with the growth of the vegetables in your garden.  

Factsheet from the Entomological Society of America 

Weed Control

Weeds are a constant problem for all gardeners.  Weeds compete with the plants in your garden for nutrients and resources.  Weeds can also introduce insect pests and diseases into the garden.  Effective weed control is essential for ensuring that your garden will have healthy and productive plants.  Weeds can be managed with mechanical, chemical, mulch and weed fabric.

Mechanical 

You can control weeds by cultivation and periodically hand pulling the weeds throughout the growing season.  Begin your control efforts early in the growing season when the weeds are small and easier to eradicate.  If cultivating avoid deep tillage since it brings more weeds to the surface and can cause the soil to dry out more rapidly.

Chemical

Organic herbicides (pesticides used to control weeds) and non-organic herbicides can also be used to control the weeds in your garden.

There are basically two types of herbicides: pre-emergent and post-emergent.  Pre-emergent herbicides control the germinating seeds before plants emerge from the soil. They won’t control weeds that have already emerged and are growing in the garden.  Post-emergent herbicides are used to control weeds that have already emerged. The younger the weed, the better chance that a post-emergence herbicide will work.  In addition to herbicides being pre or post-emergent, herbicides can also be non-selective and selective.  Herbicides that kill most plants they contact are called non-selective.  While herbicides that control some kinds of plants but not others are called selective herbicides.

A few things to remember

• Always identify the weed you are trying to control.  
• Check that the herbicide label lists the weed you are trying to control.  
• Verify that the weed is in a stage that can be controlled by the herbicide.  
• Make sure that the herbicide is safe to use around the other plants in your garden.  
• Remember, a non-selective herbicide will kill all plants susceptible to the herbicide and not just weeds.

Always, try to minimize the use of pesticides that pollute our waterways. Whenever possible use non-chemical alternatives or less toxic pesticide products . Read product labels carefully and follow instructions on the proper use, storage and disposal.

Mulch

Mulch is an effective way to help prevent weeds in gardens. Mulch can be defined as an applied barrier of some form of organic matter. 

Benefits of Mulching 

• Reduces soil evaporative water losses. 
• Increases soil temperature 
• Controls or suppresses weeds 
• Reduces nutrient leaching during heavy rainfall. 
• May add nutrients to soil (organic mulches)

New plantings should be mulched immediately after planting. Early spring is ideal, as this conserves existing soil moisture during the period when plants are coming out of winter dormancy.  Early season application also prevents many weed seeds from germinating or emerging through the mulch if mulch is applied at recommended depths for the particular material selected. 

Weed the area well before applying mulch.  Then spread mulch over the entire planting area. Keep mulch 2-3 inches away from the base of plants to prevent conditions that encourage diseases or attract rodents. Do not form a "mulch volcano" at the bottom of the plant.  This practice provides shelter for voles in particular, which eat bark and can girdle plants entirely, resulting in plant damage or death. 

Weed Fabric 

Weed fabrics are materials woven of fabric, plastic, or paper, The fabrics are available in various lengths and widths. The materials are usually treated to resist decomposition. The fabric's materials are constructed to allow water and air to move through the fabric. Weed barriers work well on most weeds, although some grasses may grow up through the holes in the fabric. Weed fabric and landscape cloth work best when they are pinned down so that weeds cannot lift up fabric. Moisture, temperature, and weed control can be improved by adding several inches of another organic mulching material on top of the weed fabric/landscape cloth.

Additional Information

Soil Testing Lab - Rutgers University - NJAES

Lamb Brothers System of Container Gardening - University of Arkansas Cooperative Extension

Raised Bed Gardens - University of Minnesota Extension

Soil for Raised Bed Gardens - Rutgers University - NJAES

Planning a Vegetable Garden - Rutgers University - NJAES

Drip Irrigation for Home Gardens - Colorado State Extension

New Jersey Weed Gallery - Rutgers University - NJAES

Weed Management - University of Illinois Extension

Weed Control for Vegetable Gardens - University of Georgia Extension

Mulches for Vegetable Gardens - Rutgers University - NJAES

New Jersey Invasive Strike Team - Herbicide Use Suggestions - FoHVOS

Integrated Pest Management - UC Davis - SAREP