Making the Most of the Soil You ve Got Mary Hagedorn
College of Agriculture and Natural Resources 2
Topics Soils of Maryland & Montgomery County Soil Basics (origin, texture, profile) Learning what kind of soil you have Soil amendment Strategies for poor soil Plants for different soils
Maryland Clay? A common question: How do I garden in Maryland clay? Do you really have a clayey soil? There are more than 750 types of soil in the state of Maryland. There are 40 types of soil in Montgomery County.
Montgomery County Soils
Acid soil in Maryland? Many Maryland gardeners think that soil in our area is acidic. Soil ph levels vary quite a bit throughout our region. A soil test can tell you the ph level of soil in your yard and garden.
Soil Basics: Formation Parent materials: Weathered rock Climate: Rain, freeze/thaw cycles, humidity, growing season length Living organisms: Worms, bacteria, fungi Topography: Erosion Time: Geological time; 500 years for 1 of topsoil
Soil Basics: Composition
Soil Basics: Composition Minerals in soil (about 45%) include silt, sand, and clay. Pores space for air and water essential for root growth transmission of air, water, and nutrients Organic matter: includes decayed leaves and plants, manure, etc. Fact sheet FS 640: Basic Principles of Soil Fertility II: Soil Properties
Soil Basics: Particle sizes
Soil Basics: Horizons/ Soil Profile O: Organic 0 to 2 from surface A: Topsoil 3 to 10 from surface B: Subsoil 11 to 30 from surface C: Substratum 30 to 48 from surface US Department of Agriculture: http://soils.usda.gov/
Impacts on Soil Profile Many of us live in housing developments. Construction involves moving earth. Layers are overturned and mixed. Heavy equipment causes compaction.
Soil Basics: Soil texture
Soil Basics: Soil tilth Soil suitability to support plant life, particularly, root growth. Aggregates (crumbs) of sand/silt/clay; pore spaces for water and air; adequate nutrients. We often focus on fertility and pests; many plant problems result from soil tilth issues.
Soil ph Soil ph is a measure of hydrogen ion concentration. 7.0 is neutral Below 7.0 is acidic ( sour soil ) Above 7.0 is alkaline ( sweet soil ) Soil nutrients are most available to plant roots and microbial activity is greatest when soil ph is in the 5.5 to 7.0 range. Plants may show symptoms of nutrient deficiency or toxicity at very high or low soil ph.
Your soil? What kind of soil do you have? Why is it important? How do you find out?
Your soil: Why it s important Soil texture determines activity in the soil. Sandy soils: Large air space, low water holding, high leaching, low nutrient retention, low erosion. Loams: Good air space, moderate in water holding/ leaching/nutrient retention, but high in erosion. Clay: High water retention impedes drainage, small air spaces, high nutrient retention, but poor nutrient exchange.
Your soil: Why it s important Soil drainage is affected by compaction and is a factor in oxygen availability. Good drainage prevents rotting of roots and bulbs. Soil ph is related to the availability of nutrients and plant needs.
Finding out what you ve got Soil test by laboratory Nutrients Ph (acidity/alkalinity) Organic matter Soil texture Other tests by request: e.g., lead, micro-organisms Choose lab time, cost, tests included Soil sampling Take samples from various locations in your yard. Send to lab in container they provide. Receive report in a few days to a couple of weeks. Fact Sheets 11, 110, 110a on soil testing and laboratories
Finding out what you ve got Soil Test Report: A&L Eastern Laboratories
Finding out what you ve got Soil Test Report: A&L Eastern Laboratories Consider Maryland laws/guidelines in fertilizing. https://extension.umd.edu/hgic/soils/fertilizer
Finding out what you ve got Do-it-yourself (not a substitute for lab test) Home test kit Ph test or meter Jar test of soil texture Ribbon test
The Jar Test Take sample, remove roots, insects, rocks. Allow to dry, crush soil. Place in jar, add 1 tsp dishwasher detergent, add water. Shake vigorously several minutes. Measure layers.
The Jar Test
The Ribbon Test Make a ball of soil in hand; press into a log shape. Hold in closed hand. Use thumb to push out a ribbon. Won t form a ball? Sand. Weak ribbon less than 1? Loam. Ribbon of 1 to 2? Clay loam. Ribbon of 2 or more? Clay.
Drainage (perc) test Dig a hole a foot deep. Fill with water and allow water to drain. Fill again and measure depth. Check how long it takes to drain. Less than 1 per hour is poor drainage. 1 to 6 per hour is desirable. More than 6 per hour is excessive drainage.
Amending Soil The surest way to improve plant growth is the regular incorporation of organic matter such as composted yard waste. Organic matter improves soil structure, slowly releases nutrients, and increases beneficial microbial activity. Fact Sheet HG 42: Soil Amendments and Fertilizers
Amending Soil Most garden and landscape plants perform best in soils high in organic matter. Greater than 3% organic matter, by weight, in the topsoil Well amended soil is loose, easy to work, has large number of earthworms.
Amending Soil: Buy or Make Your Own Compost: Commercial or home-grown Humus: End product of composting process Peat moss: Mined from prehistoric nonrenewable bogs LeafGro: Composted leaves and yard debris Manure: Available from some local farms Coconut coir: Renewable and does not repel water like peat moss Fact Sheet HG 42: Soil Amendments and Fertilizers
Amending Soil Mushroom compost: Used or spent compost from mushroom farming Pine bark fines: Finely shredded pine bark Sand: Coarse builder s sand (not play sand) Gypsum: Calcium sulfate Sawdust: Must be well-decayed Fireplace ash: Highly alkaline Fact Sheet HG 42: Soil Amendments and Fertilizers
Amending Soil Topsoil: Nonrenewable 1 requires 500 years No state or federal standards Quality will vary Inspect topsoil, ask for references Ask about source and any testing Avoid very sticky, grayish, mottled, soils that smell bad Blended topsoil & compost mixes 70% topsoil and 30% leaf compost Excellent for an instant raised bed garden Can be purchased by the cubic yard Fact Sheet HG 42: Soil Amendments and Fertilizers
Amending Soil: Changing ph Lowering ph: Acidifiers Iron sulfate Sulfur (elemental sulfur) Miracid temporary effect Holly Tone plant food containing sulfur Aluminum sulfate: not recommended (possible toxic aluminum build-up) Fact Sheet HG 42: Soil Amendments and Fertilizers
Amending Soil: Changing ph Raising ph: Lime Aragonite Agricultural limestone Hydrated lime Burnt lime ( quick lime ) Dolomitic Pelletized lime Wood Ash Fact Sheet HG 42: Soil Amendments and Fertilizers
Ongoing amendment Top dressing Spot amendment Between existing plants When adding new plants When dividing or moving perennials Dig in lightly: no till
Timing is important! Amend soil when it is neither too wet nor too dry. Under both conditions, may affect soil structure. Working soil that is too wet can increase the compaction of the soil. Working soil that is very dry can contribute to wind erosion. And it s just plain harder!
For problem drainage: Double digging
Raised beds Soil level higher than surrounding soil Benefits: Better soil condition Root room Easier to work Higher yields of vegetables Pest control
Raised beds Double-dug and raised soil No soil addition, no structure
Raised beds: Structures Wood: Not pressure treated lumber or railroad ties. Cinder blocks: They get hot. New ones can be alkaline.
Raised beds: Structures Photos: Gardener s Supply Company
Cover your soil Bare soil is subject to Moisture loss through evaporation Erosion (wind and rain) Compaction (rain) Mulch Organic: shredded bark, shredded leaves, grass clippings, compost Inorganic: gravel, marble chips (alkaline), sand Films: plastic, wet newspaper
Cover your soil Groundcover plants Look for native and/or noninvasive plants Avoid invasive plants HG 89: Ground Covers HG 120pfv: Native Plants of Maryland
ph and plant selection Many plants are tolerant of a range of ph values. Highly acidic or highly alkaline soil may pose problems for some plants. Acid-loving plants: Some prefer quite acidic soil, including azalea holly, sweetbay magnolia, pachysandra. Know your ph and select appropriate plants.
Making the most of your soil? Learn what you have. Amend, amend, amend. Use strategies to overcome problem areas. Double digging Raised beds Select plants suitable to your soil.
Resources Home and Garden Information Center (HGIC) Publications https://extension.umd.edu/hgic/home-and-gardeninformation-center-and-grow-it-eat-it-publications United States Department of Agriculture: National Resources Conservation Service http://soils.usda.gov/
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This program was brought to you by The Montgomery County Master Gardener Volunteers University of Maryland Extension