Raised Bed Plant Calculator: How Many Plants Fit in Your Garden?

Author: Jagdish Reddy | 10+ Years of Gardening Experience
Reviewed Against: University of Minnesota Extension; USDA Plant Hardiness Zone Map
Last Updated: June 2026

A raised bed filled with poor spacing or the wrong mix of crops will underperform no matter how good the soil is. This raised bed plant calculator guide gives you the exact numbers you need: plant counts by bed size, spacing by crop, yield estimates, companion planting pairings, and layout ideas from beginner to family-scale.

The recommendations below focus on plant spacing, bed size, soil depth, and crop selection because those factors have the biggest impact on harvests.

Use the calculator below to estimate how many vegetables your raised bed can comfortably support based on its size and the crops you want to grow.

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How Many Plants Fit in a 4×8 Raised Bed?

A standard 4×8 raised bed provides 32 square feet of growing space and can typically hold:

• 8 tomato plants
• 18 pepper plants
• 32 lettuce plants
• 128 carrots

Actual capacity depends on plant spacing, growth habit, and whether crops are grown vertically.

Quick Reference: Raised Bed Size Comparison

Not sure which bed size fits your goals? This table covers the key numbers in one place:

Bed Size	Sq Ft	Soil (12″ deep)	Best For
4×4 ft	16 sq ft	16 cu ft	Herbs, greens, 1-2 crops
4×8 ft	32 sq ft	32 cu ft	Mixed veggie garden
4×12 ft	48 sq ft	48 cu ft	Family of 2-3
4×16 ft	64 sq ft	64 cu ft	Large harvest, succession
3×6 ft	18 sq ft	18 cu ft	Small patio or balcony
2×8 ft	16 sq ft	16 cu ft	Cut flowers, herbs

Raised Bed Plant Count Matrix

Use this matrix as a quick reference for estimating how many plants fit in common raised bed sizes at standard square foot gardening spacing. Use the matrix below for quick planning, then use the calculators throughout this guide for custom bed sizes, spacing adjustments, and planting schedules.

Visual Raised Bed Layout Planner

Turn your plant count into a practical garden plan with a visual layout that helps you organize crops and make the most of every square foot.

Vegetable	4×4 (16 sqft)	4×8 (32 sqft)	4×12 (48 sqft)
Tomatoes	4	8	12
Peppers	9	18	27
Cucumbers*	4	8	12
Zucchini	2	4	6
Broccoli	4	8	12
Kale	4	8	12
Bush Beans	32	64	96
Lettuce	16	32	48
Spinach	16	32	48
Carrots	64	128	192
Beets	16	32	48
Onions	16	32	48
Radishes	64	128	192
Potatoes	16	32	48
Basil	16	32	48

*Cucumbers trained vertically on a trellis. Ground-planted cucumbers need 2-3 sq ft each.

Vegetable Spacing Chart for Raised Beds

Square foot gardening assigns each crop a spacing based on plant width at maturity. The spacing column below refers to the distance between plant centers in a grid pattern, not row spacing.

Once you know how many plants fit, use this spacing calculator to determine the ideal distance between plants for healthy growth and better harvests.

Vegetable	Spacing	Plants per Sq Ft	Min Soil Depth
Tomatoes (indeterminate)	24 inches	1	18 inches
Tomatoes (determinate)	18 inches	1	18 inches
Peppers	12-18 in	1	18 inches
Cucumbers (vertical)	12 inches	1	12 inches
Zucchini	24-36 in	1	12 inches
Broccoli	18 inches	1	18 inches
Cabbage	15-18 in	1	12 inches
Kale	12-18 in	1	12 inches
Bush Beans	4-6 inches	9	8 inches
Pole Beans (vertical)	6 inches	4	12 inches
Peas (vertical)	4-6 inches	8	8 inches
Lettuce (head)	8-12 in	2	6 inches
Lettuce (loose leaf)	6 inches	4	6 inches
Spinach	6 inches	4	6 inches
Arugula	4 inches	9	6 inches
Swiss Chard	6-9 inches	4	8 inches
Carrots	3-4 inches	16	12-18 in
Beets	4 inches	9	8 inches
Radishes	3 inches	16	6 inches
Turnips	4-6 inches	9	12 inches
Onions	4 inches	9	6 inches
Garlic	6 inches	4	6 inches
Potatoes	12 inches	1	12-18 in
Basil	12 inches	1	6 inches
Parsley	6 inches	4	6 inches
Marigolds (dwarf)	6 inches	4	6 inches

Vegetable Yield Estimates per Plant in Raised Beds

Spacing tells you how many plants fit. Yield tells you what you actually get to eat. These numbers are per-plant estimates under good raised bed conditions with adequate water and nutrients:

Vegetable	Yield per Plant	Notes
Tomatoes	8-20 lbs	Indeterminate; varies by variety
Peppers	6-10 peppers	More in warm climates
Cucumbers	10-20 cucumbers	Harvest often to keep producing
Zucchini	6-10 lbs	Pick small for better taste
Broccoli	1 main head + side shoots	Side shoots extend harvest
Kale	2-3 lbs leaves	Harvest outer leaves continuously
Bush Beans	0.5-1 lb per plant	Multiple harvests per plant
Lettuce	0.25-0.5 lb	Head; more for loose leaf cuts
Spinach	0.25-0.5 lb	3-4 cuts before bolting
Carrots	1-2 medium carrots	Per seed/plant
Beets	1 root + greens	Greens are edible too
Potatoes	2-5 lbs	Varies by variety and depth
Onions	1 bulb	Plus green tops during growth

These numbers assume healthy soil, consistent watering, and no major pest pressure. Climate plays a large role: tomatoes in Zone 9 can double the yield of the same plant grown in Zone 5.

How Many Plants Fit in Common Raised Bed Sizes?

4×4 Raised Bed Planting Plan

A well-planned 4×4 bed supplies one person with steady salad greens, herbs, and a few fruiting vegetables.

Sample 4×4 plan for a beginner:

• 1 tomato (back corner, with cage)
• 2 peppers (adjacent to tomato)
• 1 basil plant (next to tomatoes)
• 4 head lettuce (front section)
• 9 onions (side section)
• 16 radishes (fill gaps between slower crops)

4×8 Raised Bed Planting Plan

A 4×8 bed works well for one or two people. Divide it into two halves: warm-season crops on one end, cool-season crops or herbs on the other.

Sample 4×8 high-yield plan:

• 2 indeterminate tomatoes (north end, staked)
• 2 cucumbers on a trellis (north end, beside tomatoes)
• 4 peppers (middle section)
• 1 row bush beans (9 plants)
• 1 block lettuce (8 plants)
• 1 block spinach (8 plants)
• Herbs: basil, parsley, chives (fill remaining space)

4×12 Raised Bed Planting Plan

A 4×12 bed suits a family of two to three, especially with succession plantings of fast-maturing crops.

Sample 4×12 family plan:

• 3 tomatoes + 3 cucumbers (north trellis section)
• 6 peppers or 6 broccoli plants (center section)
• 18 bush beans (one full zone)
• 12 head lettuce + 12 spinach (cool-season zone)
• 1 full row carrots (32-48 plants, deep end of bed)

4×16 Raised Bed Planting Plan

Divide a 4×16 bed into 4-foot zones and stagger plantings every two to three weeks. This keeps lettuce, beans, and radishes producing in waves through the season.

Planning Custom Raised Bed Layouts

Multiply length by width for total square feet, then divide by each crop’s spacing. A 3×10 bed gives 30 square feet. The math is the same for any shape.

Square Foot Gardening Planting Guide

Square foot gardening divides the bed into a grid of 1-foot squares. Each square holds a different crop at its ideal spacing. The system works especially well in raised beds because the loose, deep soil supports the intensive spacing that would stress plants in a compacted in-ground garden.

The number of plants per square follows a simple pattern based on the spacing needed:

Spacing Needed	Plants per 1 Sq Ft	Example Crops
3 inches	16	Carrots, radishes, beets
4 inches	9	Onions, garlic, bush beans
6 inches	4	Lettuce, spinach, parsley
9 inches	1	Kale, chard, bok choy
12 inches	1	Peppers, basil, potatoes
18 inches	1	Broccoli, cabbage, indeterminate tomatoes (per 4 sq ft)
24 inches	1 per 4 sq ft	Tomatoes, zucchini, cantaloupe

Because raised beds are accessed from the outside, every square foot inside the bed can be used for growing crops instead of walkways.

Companion Planting Layouts for Raised Beds

These are practical companion planting pairings for common raised bed crops:

Tomato Companion Planting

Plant with Tomatoes	Benefit	Spacing Notes
Basil	Deters aphids and whitefly	Plant 12″ from tomato stem
Marigolds	Repels nematodes and aphids	Border or edge of bed
Carrots	Loosen soil around tomato roots	Plant in gaps between tomatoes
Borage	Deters tomato hornworm	1 plant per 4 tomatoes
Parsley	Attracts predatory insects	Edge planting

Avoid planting tomatoes near brassicas or corn; they compete for similar nutrients.

Pepper Companion Planting

Plant with Peppers	Benefit	Notes
Basil	Improves flavor, deters aphids	Close planting fine
Tomatoes	Similar needs, good neighbors	Keep spacing; both need support
Spinach	Ground cover, retains moisture	Plant in pepper shadow areas
Marigolds	Pest deterrent	Border planting
Carrots	Do not compete for above-ground space	Fill gaps below peppers

Avoid peppers near fennel, which inhibits most vegetables.

Cucumber Companion Planting

Plant with Cucumbers	Benefit	Notes
Beans	Fix nitrogen that cucumbers need	Plant at trellis base
Nasturtiums	Trap crop for aphids	Let them sprawl at bed edge
Dill	Attracts beneficial insects	Keep young; mature dill can inhibit
Corn	Provides natural trellis	Only in very large beds
Radishes	Deter cucumber beetles	Direct sow between cucumbers

Vegetables to Avoid Planting Together

Avoid This Combination	Reason
Fennel + anything	Inhibits most vegetables; grow alone
Onions + beans/peas	Onions stunt legume growth
Brassicas + tomatoes	Compete for nutrients; can stunt each other
Potatoes + tomatoes	Share blight disease; keep separated
Dill (mature) + carrots	Cross-pollinate and reduce quality
Garlic + beans/peas	Garlic suppresses legume root activity

Crop Rotation for Raised Beds

Rotating crops prevents nutrient depletion and breaks pest cycles. In a raised bed the soil is confined, so repeating crops in the same spot depletes the same nutrients each year.

A simple four-group rotation works well for most home gardens:

Group	Crops	Year Rotation
Fruiting	Tomatoes, peppers, cucumbers, squash	Year 1
Brassicas	Broccoli, cabbage, kale, turnips	Year 2
Root Crops	Carrots, beets, onions, garlic, potatoes	Year 3
Legumes	Beans, peas (nitrogen fixers)	Year 4

If you only have one or two raised beds, rotate the fruiting and legume groups at minimum. The fruiting group exhausts the most nitrogen. Legumes restore it. Even alternating just those two makes a measurable difference in year-two productivity.

Seasonal Garden Planning for Raised Beds

Your planting dates depend heavily on local frost timing. Use the calculator below to estimate the average last and first frost dates for your area.

Once you have your frost dates, use this tool to calculate the right indoor seed starting dates for each crop you plan to grow.

Spring Garden Planning (Weeks Before Last Frost)

Cool-season vegetables can go in the ground weeks before the last frost. Raised beds warm up faster than in-ground soil, which gives you an even earlier start than the standard calendar suggests.

Timing	What to Do	Crops
8 weeks before last frost	Start indoors	Tomatoes, peppers, broccoli, kale
6 weeks before last frost	Direct sow in bed	Peas, spinach, lettuce, radishes
4 weeks before last frost	Transplant cold-tolerant crops	Broccoli, kale, chard
After last frost	Transplant warm crops	Tomatoes, peppers, cucumbers, beans
2 weeks after last frost	Direct sow warm crops	Beans, squash, cucumbers, basil

Fall Garden Planning (Weeks Before First Frost)

A second cool-season window opens in late summer. Count back from your expected first fall frost date to plan transplant timing. Raised beds also extend the fall season because the soil holds warmth longer than ground soil.

Timing	What to Do	Crops
10 weeks before first frost	Start indoors or direct sow	Broccoli, cabbage, kale
8 weeks before first frost	Direct sow	Carrots, beets, turnips
6 weeks before first frost	Transplant or direct sow	Lettuce, spinach, arugula
4 weeks before first frost	Direct sow fast crops	Radishes, green onions

A cold frame or row cover over your raised bed can add another four to six weeks to either end of the season. This is especially useful in Zones 5 and 6 where the shoulder seasons are short.

Raised Bed Planting Guide by USDA Hardiness Zone

Zone determines how long your growing season is, when frosts happen, and which crops thrive in your climate. A raised bed plan that works in Georgia will not transfer directly to Minnesota without adjustments.

Zones 3-4 (Short Season: 90-120 Frost-Free Days)

Focus on fast-maturing varieties. Last frost often falls in late May or early June.

Focus Crops	Maturity (Days)	Notes
Lettuce, spinach, arugula	30-50 days	Direct sow early; succession plant
Radishes	25-30 days	Fastest crop for short seasons
Bush beans	50-60 days	Choose short-season varieties
Broccoli	55-70 days	Spring and fall planting window
Carrots	60-75 days	Look for varieties under 70 days
Short-season tomatoes	55-70 days	‘Stupice’ or ‘Glacier’ varieties

Zones 5-6 (Medium Season: 140-180 Frost-Free Days)

Two growing windows are available: a cool-season spring and a warm summer with a fall shoulder season.

Season	Crops	Notes
Cool season (Mar-May)	Peas, lettuce, spinach, broccoli, beets	Direct sow 4-6 wks before last frost
Warm season (May-Sep)	Tomatoes, peppers, cucumbers, squash	Transplant after last frost date
Fall season (Aug-Oct)	Kale, lettuce, carrots, chard	Start 8-10 wks before first fall frost

Zones 7-8 (Long Season: 180-220 Frost-Free Days)

The challenge shifts to managing heat. Cool-season crops bolt quickly in summer, so time them for spring and fall windows.

Season	Crops	Notes
Winter/early spring (Jan-Mar)	Greens, root veg, peas	Often direct sow; light frost protection
Spring (Mar-May)	Tomatoes, peppers, beans	Transplant after last frost (Mar-Apr)
Summer (Jun-Aug)	Heat-tolerant crops only	Sweet potatoes, okra, Southern peas
Fall (Sep-Nov)	Broccoli, cabbage, root crops	Main brassica season in this zone

Zones 9-10 (Near Year-Round: 240-365 Frost-Free Days)

Growing is possible nearly year-round. Cool-season crops go in fall through early spring. Summer heat above 100 degrees Fahrenheit limits most vegetables.

Season	Crops	Notes
Fall/Winter (Oct-Feb)	Tomatoes, peppers, greens, root veg	Main growing season; cool enough for most crops
Spring (Feb-Apr)	Cucumbers, squash, beans, corn	Plant before heat peaks
Summer (May-Sep)	Okra, sweet potatoes, Malabar spinach	Most crops struggle above 100F

What Soil Depth Is Best for a Raised Bed?

Most vegetables grow well in 12 inches of soil. Leafy greens can succeed in 6 inches, while root crops such as carrots, parsnips, and potatoes benefit from 18 to 24 inches. Shallower beds dry out faster and restrict root development, which reduces yield on any crop.

Raised Bed Soil Calculator: Depth and Volume

A raised bed filled with poor soil will struggle no matter how carefully you space the plants. The quality of your soil has a major influence on plant health, root development, and harvest size.

Calculate exactly how much soil your raised bed needs so you can create the right growing environment before planting.

How Much Soil Does a Raised Bed Need?

Multiply length x width x depth (in feet) to get cubic feet. Divide by 27 for cubic yards. Most bags of garden soil are sold in cubic feet (labeled on the bag), so cubic feet is the more useful unit for most people.

Bed Size	6″ Depth	12″ Depth	18″ Depth
4×4 ft	8 cu ft	16 cu ft	24 cu ft
4×8 ft	16 cu ft	32 cu ft	48 cu ft
4×12 ft	24 cu ft	48 cu ft	72 cu ft
4×16 ft	32 cu ft	64 cu ft	96 cu ft
3×6 ft	9 cu ft	18 cu ft	27 cu ft

Soil Depth by Crop Type

Soil Depth	Suitable Crops	Not Suitable For
6 inches	Lettuce, herbs, radishes, spinach	Tomatoes, carrots, potatoes
12 inches	Tomatoes, peppers, beans, beets, onions	Deep carrots, parsnips
18-24 in	Carrots, parsnips, potatoes, squash	No restrictions at this depth

Best Soil Mix for Raised Beds

The classic square foot gardening mix (sometimes called Mel’s Mix) is one-third compost, one-third peat moss or coconut coir, and one-third coarse vermiculite or perlite. It stays loose over years, drains well, and holds enough moisture to need less frequent watering than native soil.

When refreshing older beds, our compost calculator can help estimate how much compost to add before planting.

Refresh the bed each spring with 1 to 2 inches of finished compost worked into the top 4 to 6 inches. Soil in raised beds compresses and decomposes faster than in-ground beds because of the higher air and water movement through the profile.

Raised Bed Layout Plans for Beginners, Families, and Small Spaces

Beginner Raised Bed Layout (4×8)

Pick four or five crops you cook with regularly.

• North end: 2 tomatoes with cages (they get tallest, shade behind them)
• Center: 4 peppers
• South end: 8 lettuce + 4 basil plants
• Fill gaps: radishes or onions

High-Yield Raised Bed Layout (4×8 or 4×12)

• North trellis: cucumbers and pole beans (doubles vertical space)
• Mid-bed: bush beans (high yield per square foot)
• Front section: cut-and-come-again greens (continuous harvest)
• Corners: marigolds for pest deterrence

Small-Space Raised Bed Layout (4×4)

Avoid sprawling crops in a 4×4 unless you have a trellis. Use compact varieties:

• 1 cherry tomato (determinate or compact variety)
• 2 dwarf peppers
• 4-6 loose-leaf lettuce plants
• 9 onions or garlic
• 1 cluster of herbs (basil, parsley, chives sharing 2-3 squares)

Family Vegetable Garden Plan (Two 4×8 Beds)

Two 4×8 beds, one for warm-season crops and one for cool-season crops, covers the calendar for a family of three to four. Rotate each year to break pest cycles.

Bed	Season	Crops
Bed A	Warm season	3 tomatoes, 3 cucumbers, 4 peppers, 1 zucchini
Bed B	Cool season	Broccoli, kale, carrots, beets, lettuce, spinach
Bed A (fall)	Cool season succession	Swap to kale, chard, lettuce after tomatoes finish
Bed B (summer)	Warm season succession	Direct sow beans, replace finished brassicas

Common Raised Bed Planning Mistakes

Overcrowding Plants

Spacing recommendations exist for a reason. Plants that are too close together compete for nutrients and light, trap moisture that leads to fungal disease, and often produce less than a properly spaced bed with fewer plants.

Ignoring Mature Plant Size

A tomato seedling looks small in May. By August it can be five feet tall and three feet wide. Always plan for the mature size of each crop, not the transplant size.

Not Accounting for Soil Depth

A 6-inch deep raised bed will not support tomatoes, peppers, or root vegetables well. Build or fill the bed to the correct depth for your crops before you plant. It is much harder to add depth after the bed is in use.

Planting Warm-Season Crops Too Early

Tomatoes, peppers, cucumbers, and beans all need warm soil. Planting them before the soil reaches at least 60 degrees Fahrenheit slows germination, stresses transplants, and invites disease. The extra week of waiting usually pays off in faster establishment.

How to Maximize Harvests in a Raised Bed

Avoid Overcrowding

Overcrowded plants compete for light, water, and nutrients. They also trap moisture between leaves, which is how fungal disease gets started. When spacing feels tight, pull to the wider end of the recommended range.

A bed with 8 well-spaced peppers will outproduce a bed with 12 crowded ones. The yield per plant goes up when roots have room to develop properly.

Use Vertical Growing to Double Space

Trellises, cages, and stakes allow climbing crops to go up instead of out. Cucumbers, pole beans, indeterminate tomatoes, and peas all grow well vertically. Position the trellis on the north side of the bed so it does not block sun from shorter plants.

Succession Planting Keeps Beds Productive

Pull a finished crop and immediately replace it. When spring lettuce bolts in June, transplant a pepper seedling into that square. When early beans finish, direct sow a second batch or start a fall brassica. When one crop finishes, replant the space with another crop suited to the season.

Here is a practical succession guide for a 4×8 bed in Zones 5-7. Adjust timing based on your local frost dates:

Month	Finish / Remove	Replace With
May	Spinach (bolting)	Peppers or eggplant
June	Lettuce (bolting)	Beans or cucumbers
July	Radishes	Beets or more beans
August	Bush beans (finished)	Kale or broccoli starts
September	Summer squash	Lettuce, spinach, arugula

Water Deeply, Not Frequently

Shallow frequent watering keeps roots near the surface. Deep watering once or twice a week drives roots down into the full depth of the bed. This makes plants more drought-tolerant and produces stronger root systems. Drip irrigation or soaker hose is ideal for raised beds because it keeps foliage dry.

If plants start showing yellow leaves, spots, curling, or poor growth during the season, our plant diagnosis tool can help identify common vegetable garden problems and potential nutrient deficiencies.

Frequently Asked Questions

How many plants fit in a raised bed?

It depends on bed size and crop spacing. A 4×8 raised bed fits 8 tomatoes, 18 peppers, 32 lettuce plants, or around 128 carrots. Use the plant count matrix in this guide to find exact numbers for your bed size and chosen crops.

What is the best spacing for raised bed vegetables?

Square foot gardening spacing works well in raised beds because the deep, loose soil allows more intensive planting than in-ground rows. Most vegetables have a recommended spacing on the seed packet. In fertile raised bed soil, you can use the closer end of that range safely.

How deep should a raised bed be?

Twelve inches works for most vegetables. Lettuce and herbs do fine in 6 inches. Carrots, parsnips, and potatoes benefit from 18 to 24 inches. Shallower beds dry out faster and restrict root development, which limits yield on any crop.

Can you use square foot gardening in a raised bed?

Yes, and raised beds are the ideal environment for it. The contained, amended soil supports intensive spacing that would stress plants in compacted ground soil. Divide the bed into 1-foot squares and assign each section to one crop at its recommended spacing.

What size raised bed is best for a beginner?

A 4×8 raised bed is the most practical starting point. It gives 32 square feet, fits a meaningful variety of crops, stays reachable from both sides without stepping into the bed, and is small enough to fill and maintain without a large upfront investment.

What vegetables grow best in raised beds?

Tomatoes, peppers, cucumbers, lettuce, spinach, carrots, onions, beans, and most culinary herbs perform exceptionally well in raised beds because the soil warms faster, drains better, and allows more precise spacing than traditional garden rows.

Can you grow vegetables year-round in a raised bed?

In Zones 7 and warmer, year-round growing is possible with the right crop selection. In colder zones, a cold frame, row cover, or hoop house over the raised bed can extend the season by four to six weeks on each end. Most gardeners in Zones 5-6 can grow from March through November with season extension.

How often should raised beds be watered?

Most raised beds need watering one to two times per week during the growing season. Because raised bed soil drains faster than ground soil, it also dries out faster. Check soil moisture by inserting a finger two inches deep. Water when it feels dry at that depth. A drip irrigation system or soaker hose keeps watering consistent and reduces foliar disease.

How to Plan a Raised Bed Garden

Follow these steps to go from an empty bed to a full planting schedule:

1. Measure your raised bed dimensions.
2. Use the plant calculator to estimate capacity.
3. Check spacing requirements for each crop you want to grow.
4. Create a layout plan that groups crops by height and spacing.
5. Calculate soil volume needed based on bed dimensions and depth.
6. Find your last and first frost dates for your area.
7. Calculate seed-starting dates by counting back from your last frost.
8. Plant according to your schedule, starting with seeds indoors and transplanting after frost.

Build Your Raised Bed Plan

Use this five-step framework to put together a complete plan before you plant:

1. Choose your bed size. Start with a 4×8 if you are new to raised bed gardening.
2. Select your crops. Pick 4 to 6 vegetables you actually cook with and check their spacing requirements.
3. Check plant spacing. Use the plant count matrix and spacing chart in this guide to confirm how many plants fit.
4. Calculate your soil. Multiply length x width x depth for total cubic feet needed.
5. Set planting dates. Use your last frost date to work backward from transplant day and determine when to start seeds indoors.

Helpful Resources

• USDA Plant Hardiness Zone Map
• University of Minnesota Extension – Raised Bed Gardening

Disclaimer: Gardening information on Garden Truth is for educational purposes only. Results vary by climate, soil, weather, and growing conditions. For region-specific advice, consult your local USDA Cooperative Extension Service before making major gardening or soil changes.