In this workshop, instructor Erin Higgins, the Education and Giving Grove Coordinator at The Big Garden, teaches you how to prepare a bed for planting and proper planting techniques for seeds & seedlings. She also shares when to plant different varieties and explains bio-intensive planting, which will help you get the most out of your small garden.
The following calendars, charts, and tools can be found online. Just follow the links. When seeking out other guides, calendars, and tools on your own, keep in mind which USDA Hardiness Zone you’re growing in. In Omaha, we’re in zone 5b. Your local university’s extension can be a great, localized resource, but often online tools are customizable.
WHAT IS SOIL?
and why is it so important?
SOIL is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life.
AN IDEAL SOIL has the following composition: 25% water, 25% air, roughly 45% minerals, and 3-5% organic matter.
THE MINERAL COMPONENT of soil is some mixture of sand, silt, and clay. Sand particles are very large, silt particles are relatively small, and clay particles are very, very small. Every soil has these particles in varying proportions, and there is very little you can do to change these ratios.
THE ORGANIC COMPONENT of your soil is made up of both macro- and micro-organisms. Living things like nematodes, earthworms, beetles, bacteria, fungi, and protozoa. It also consists of dead plant and animal matter in varying states of decay. You can add organic matter to your soil in the form of compost or living or dead plant matter (i.e. mulches or plant residue from harvested crops).
A full half of an ideal soil is made up of WATER AND AIR which all of the living organisms in your soil and the plants you want to grow need to sustain their lives. This is why COMPACTION is something we want to avoid. Soil becomes compacted, and the pockets of air and water disappear, when we step on soil unnecessarily and when we use excessive tillage.
Healthy soils are teeming with life. Researchers have calculated that a double handful of biologically active soil will contain more units of life than there are people on the face of the earth. And these organisms form an INTRICATE ECOSYSTEM that has developed over millennia. A smart gardener doesn’t think about just feeding the plants that they want to grow, but more importantly feeding and supporting this intricate ecosystem of organisms.
why they're important and how to build them
SOIL AGGREGATES are groups of soil particles that bind to each other more strongly than to adjacent particles.
The space between the aggregates and within the aggregates provide pore space for retention and exchange of the AIR AND WATER that is so important for all of the living organisms in the soil. The larger pores between aggregates also allow space for roots to move down through the soil.
YOU CAN PROMOTE AGGREGATION IN YOUR SOIL
Certain aspects of your soil will lead to or detract from its ability to form aggregates regardless of what you do. Soils with higher clay content or higher iron and aluminium oxide content tend to aggregate better. A soil test will help you determine what you’re working with in terms of these properties.
More importantly, though, certain practices can increase soil aggregation. These things are in your control.
Adding organic matter to your soil promotes aggregation. As the micro-organisms in the soil break down the organic matter, they create and secrete compounds that act almost like a glue to bind soil particles together.
Keeping roots in the soil as much as possible promotes aggregation. Living roots produce and secrete what is called root exudates which also act as a glue. As you plan out your garden for the year, think about successive plantings. For example, once you harvest your spring peas, can you use that space for a summer or fall crop like squash? Also consider growing cover crops when you aren’t going to have a harvestable crop in the soil.
Focusing on fungus can also promote soil aggregation. As fungus, such as mycorrhizal, weave their way through the soil, they bind particles together. Fungi love woody plant material, so think about growing perennial crops like raspberries or wild plums. Or utilize wood mulches to keep your ground covered.
YOU CAN ALSO DESTROY SOIL AGGREGATES
When you till you are violently breaking up all of your soil aggregates into finer particles. This allows the soil to become compacted, reduces moisture retention and proper drainage, and leads to soil erosion and loss of organic matter. As much as possible, utilize no-till or low-till techniques in your garden.
WHAT ABOUT HUMUS?
humin, humic acid, and fulvic acid
All fertile soil contains several components: decomposing organic matter, living organisms (including plant roots, bacteria, fungus, worms, nematodes, protozoa, and small animals), and HUMUS –
HUMUS is the carbon-rich matrix made of fully decomposed organic matter and is found in any soil containing decomposed organic matter, as well as in compost, worm castings, sphagnum peat moss, and other aged organic matter.
The older and darker in color that a soil is, the more humus it contains.
Humus is made up of lignins, fats, and sugars, as well as three types of chemical compounds called “humic substances”: humin, humic acids, and fulvic acids.
The electronegativity factor of humic and fulvic acids is key in developing and maintaining healthy and sustainable soil. Humic acid and fulvic acid are large, negatively charged particles. And thus attract and bind to positively charged ions, which are all of those nutrients a plant needs (e.g. Mg+, Ca+, Na+, P+, etc.). These large acids then move through the soil to the depletion zone of roots and mycorrhizal fungus, which are also negatively charged, and hand over the nutrients to the roots and fungus.
To PROMOTE HUMUS FORMATION, first make sure that you’re consistently adding organic matter to your soil, in the form of compost or living and dead plant material. Second, keep those living organisms in mind at all times. The earthworms and beetles will break down larger pieces of organic matter before the bacteria, fungi, and protozoa take over and continue the process of breaking down the organic matter into its final state: Humus.
THE RULES FOR HEALTHY SOIL
building humus and promoting aggregation
KEEP YOUR SOIL COVERED. The soil should never be naked. Nude soils promote erosion, evaporation of soil water, leaching and outgassing of nutrients; they weaken soil biodiversity and the nutrient base of the plant symbionts; they reduce capacity of the ground for assimilation of atmospheric carbon, nitrogen, and water. Soil cover can be achieved by means of mulching crop residues or cover cropping systems.
DON’T DISTURB THE SOIL. Use low or minimum tillage to maintain the soil structure and prevent compaction. Tilling and inverting soil layers expose organic matter to oxidation, converting it to CO2 lost to the atmosphere. It also disturbs complex soil ecosystems, impoverishing the soil food web.
RETURN NUTRIENTS TO THE SOIL. Use crop residues, compost, and animal manure. Return the nutrients that have been removed from the soil.
DIVERSITY IS KEY. Diverse mixed plantings promote soil biodiversity, improving biological nutrient fixation and increasing disease resistance of the ecosystem.
CONSIDER PERENNIALS. Once a perennial planting is established, it becomes a no-till area by nature. You’ll likely want to mulch a perennial area to prevent weed suppression or use living mulches like clover which means the soil will be covered. The deep root systems of perennials bring nutrients from further down in the soil profile. And perennials provide food (sugars) to the microbial life in the soil year-round, keeping the soil food web complete.
CROP ROTATION. This is a tidier way to mimic diversity. Using a minimum three-field rotation system and mixed cropping increases biodiversity, reduces pests and diseases, and increases soil mineral availability.
USE COVER CROPS. These not only keep the soil covered which reduces a whole host of issues listed above, but they also increase humus content, act as a fertilizer by helping fix nitrogen and scavenge other nutrients, reduce weed and disease pressure, encourage beneficial insects, promote soil aggregates, add biomass to the soil, and keep the soil food web alive and thriving by providing sugars to all the microorganisms living in the soil. To promote NITROGEN FIXATION use legumes like hairy vetch and winter peas. To increase HUMUS CONTENT use more grasses and clovers.
What is CROP ROTATION?
Crop rotation is a process of grouping vegetables by botanical family, and/or by their nutrient and care requirements, and then planting them in different parts of your garden in a rotation. So legumes would be on the northwest side of your garden in year one, and then the southwest side of your garden in year two, etc.
The BENEFITS OF CROP ROTATION
It disrupts the life cycle of many organisms (insects, diseases, weeds), which otherwise would be able to take up residence more easily.
It allows plants with different root systems to penetrate the soil to different depths, thereby improving soil structure.
It reduces depletion of nutrient reserves in the soil by alternating crops with different requirements. Root vegetable, leaf vegetable, fruit vegetable.
It allows for alteration of heavy feeding crops with light feeding ones. Compost can then be applied one year out of two, for easier management.
CHOOSING THE RIGHT LOCATION
questions to ask yourself
Where will you grow? Backyard, community garden, farm, etc.
What is going on with the SOIL? If there is no existing soil test, get it tested. Especially if you might have lead or other heavy metals in your soil. Check your property's lead history here. We recommend Midwest Labs in Omaha for soil testing.
What is the landscape already doing? Notice what is growing here. What “weeds” or plants already exist? What wildlife? Is there a natural water source? Soil is living. There are millions of different species both visible and invisible around you. How can you disrupt your small ecosystem as little as possible? A garden can provide habitat + food for other species.
Is there full sun? Almost all annual vegetables and fruits require full sun which means 6-8 hours each day.
Is there an option for a south-facing garden? If you can select a location that faces south with nothing blocking the southern edge, your soil will warm up earlier in the season, and stay warm later into the fall.
Is there a slope? Build your garden with the slope, not against it. A gentle slope can help prevent flooding during heavy rains. A steep slope might necessitate doing more landscaping to prevent water from moving too quickly through the garden, though.
Is there water close by?
A water source must be easily accessible. Gardens need water on a very regular basis. Make it easy on yourself!
Do you need to build raised beds?
If your soil is contaminated with lead, you will need to construct raised beds instead of planting directly in the ground. You might also want raised beds if you have mobility issues or for a neater appearance. Never use treated lumber for building raised beds. To fill raised beds, use a 50/50 blend of topsoil and compost. We like to order from Soil Dynamics or Maple 85 here in Omaha.
why it's so important
You can learn a lot about your soil by getting it tested. We recommend going through Midwest Labs here in Omaha. They have a Garden Soil Testing Package that costs $15 and will tell you most of the information you’ll need about your soil: Organic Matter, Nitrate-N, Phosphorus, Potassium, pH, Magnesium, Calcium, Sodium, Soluble Salts, Buffer Exchange, and Cation Exchange Capacity.
For a great explanation of how to interpret your soil test results, go to the following link: SARE Interpreting Soil Test Results
Omaha, like many major metropolitan areas, has a terrible lead problem. Lead in soils is inhaled in the form of soil dust particles and is ingested when people either unwittingly eat soil or eat certain plants that have been grown in lead-contaminated soils. It can be very dangerous, especially for children. Long-term exposure is especially risky.
You need to get your soil tested for lead if you live in Omaha. It may have already been tested and possibly remediated, though. Check out the Omaha Lead Registry’s website.
The Simple Search is recommended. You just type in your address, click the search button, and an aerial view of your home will pop up. Click on your home, and information about whether your soil has been tested, when it was tested, what the results were, if the soil qualified for remediation, and when it was remediated will appear.
Anything below 400 ppm is considered low. We err on the side of caution at The Big Garden, though, and we do not work in soils that are about 100 ppm given that we work with so many children. This is why we build so many raised bed gardens, and you can do the same if you want to err on the same side of caution.
If you want to read more about the different classifications of lead levels, and recommendations on what to do to protect yourselves and your children if you do want to garden in soils that are fairly low, Penn State’s Extension has a great explanation.
a quick introduction
BIOINTENSIVE METHODOLOGY tries to grow as much organic food as possible in the smallest amount of space. The method draws upon a variety of intensive agricultural methods practiced thousands of years ago in China, Greece and Latin America, as well as French intensive techniques practiced in the 1700s and 1800s, and Biodynamic techniques developed in Europe in the early 1920s.
THE EIGHT PRINCIPLES OF THE BIOINTENSIVE METHOD are:
Raised Permabeds – to create a healthy environment for roots and soil organisms
Composting – to provide healthy, inexpensive fertilizer that keeps the soil productive
Close, Intensive Planting – to maximize efficiency and productivity, to act as a living mulch, and to conserve water
Companion Planting – to take advantage of the synergy between certain plants
Carbon Farming – growing fertilizer while growing food
Calorie Farming – growing the greatest number of calories per pound of food
The Use of Open-Pollinated Seeds – to take advantage of seed saving
A Whole-System Farming Method – using all aspects of the system to create a healthy, sustainable farm
CLOSE, INTENSIVE PLANTING is something that might seem counter to conventional wisdom. For instance, according to any seed packet you’ll read, tomatoes should be planted 18-36 inches apart with 4-6 feet between rows. Biointensive planting guides say, though, that if you can keep every plant 18-36” away from every other plant, you can have much narrower rows.
The trick to getting your plants as close together as possible is to plant them in a triangular pattern so that every other row is offset. You can easily make your own triangles from scrap wood or even cardboard. You can make them in various sizes for different plants requiring different spacing.
and its benefits
Your final garden will look like this intricate grid of triangles and hexagons below. Each of the lettuce plants in this diagram below are 8 inches away from every other nearby plant.
BIOINTENSIVE SPACING suggests using the smallest number of any suggested range. When the plants get to three-quarters of their full size, their leaves should begin to touch. This creates a canopy or a living mulch. Underneath the canopy, weed seeds are less likely to take hold due to a lack of light. The lack of light also means water is retained for longer underneath the canopy, meaning watering needs to happen less often. Also, this method has the additional benefit of maximizing the amount of food that can be produced in a given space.
KNOWING WHEN TO PLANT
a question of soil temperature
There are tons of calendars and calculators out there that tell you the right time to plant different crops. For seeds that are going to be planted directly into the garden, the two best tools you can use, though, are a SOIL THERMOMETER and the BACK OF THE SEED PACKET. Different plants have different needs in terms of the temperature the soil needs to be in order for that seed to germinate. And if you’re ordering good quality seeds, the company will print this information on the back of your seed packet.
DIRECT SEEDING VS. TRANSPLANTING
Some plants come from climates much warmer than ours. We’re in ZONE 5B. Peppers, for example, originated in and near Mexico which is much closer to the equator. Hardiness zones in Mexico range from 9-11 which means the temperatures rarely if ever fall below freezing. This means peppers evolved with soil temperatures warming up much faster than what we see here in the Omaha area. If you try to plant a pepper seed outside once the soil is warm enough for them to germinate (between 65 and 95 degrees Fahrenheit), you won’t get the seeds in the ground until late spring or early summer. This means the plant won’t have enough time to complete its life cycle and produce fruit for us.
How do we overcome this? By starting seeds indoors. Many annual vegetables and fruits need to be started inside as early as January in order to go through their entire life cycle before our first frost in the fall. Both the High Mowing Planting Chart and The Big Garden’s Planting Calendar delineate whether a seed needs to be started indoors and then TRANSPLANTED OUT or if it can be sown directly into the garden in a process known as DIRECT SEEDING.
PREPARING YOUR IN-GROUND GARDEN
For a BRAND NEW GARDEN:
Mow the selected area.
Lay a tarp down (silage tarp is best).
Till the selected area (ONLY IN YEAR ONE!).
Remove any large dirt, rocks, debris, grass clumps.
Put tarp down again for 2-3 weeks to help suppress weeds.
Build your soil by putting down high-quality compost.
Shape your permabeds. 8 inches tall. 30 inch wide beds 18 inch walk-paths
Broadfork all beds.
Add vermicompost and compost top dressing.
Rake beds smooth.
Mulch walk-paths or seed clovers.
Put tarp down unless you are ready for planting.
For an EXISTING GARDEN:
Mow down any cover crop or cover crop residue from the previous fall. A flail mower is suggested, but a push mower can be used; you’ll just need to rake off the residue afterward.
Cover with a tarp for 2-3 weeks for weed suppression.
Spread soil amendments (vermicompost and/or high-quality organic compost).
Broadfork each bed to aerate the soil and mix in amendments.
Use the back of a rake to tamp down and smooth the bed.
Final walk through to remove any debris or stones.
Put tarp down unless you are ready for planting.
How to Prep Beds for Precision Seeding
If you don’t have a tilther to incorporate amendments, you can use a rake.
If you don’t have a roller to further flatten the soil - you can use a rake.
WHY BUILD PERMABEDS?
BETTER DRAINAGE Excess rainfall will drain away from the crop zone but stay on the root zone
SOIL WARMS FASTER Faster drying and warming allows for better germination
NO SOIL COMPACTION Never walk on the beds during the growing season, no machinery on the soil
HIGHER YIELDS Uniform spacing, high-density planting, increased yield per square foot
SOIL BUILDING Amendments like compost are not wasted but placed right on the growing area (not in the walk paths)
A hoe for mounding beds 8 inches on each side
A hard tine rake for smoothing beds
Broadfork or Pitchfork (not hayfork) for aerating soil
String/twine for making your rows and 1-foot sections Trowel
Paint sticks and sharpies for labeling
Wheel hoe or stirrup hoe
Hose(s) long enough to reach your garden with a watering wand
Watering cans can be used instead
A rain gauge
Harvest knives for cutting brassicas, cabbage, greens
BASIC GARDEN MAINTENANCE
how to care for your garden
We recommend that you check on your garden at least three times a week. Ideally, this would either be first thing in the morning or later in the evening just before sunset. While you’re outside you need to do THREE BASIC THINGS to maintain your garden.
WATER. Consistent watering is key, especially when seedlings are very young. A garden needs about two inches of water each week. Keep an eye on the forecast and on your rain gauge. Whatever doesn’t come from the sky needs to be supplemented with a hose or a watering can. Gentle watering is best, so use a watering wand with your hose and use watering cans with sprinkler heads. Water directly at the base of the plant where the roots are. Do not use overhead watering like sprinklers as these get all of the leaves wet, too, which can lead to disease issues.
WEED. Weeding is easiest if you keep up with it on a consistent basis. Never, ever let your weeds complete their life cycle and produce seeds. You can weed by hand if you like getting dirty. Otherwise, there are a variety of hoes that can be used for weeding. Our favorite is the stirrup hoe (also known as a hula hoe) because you can weed both while pulling and pushing the tool through the top inch or so of the soil.
SCOUT. If you take your time while you’re out in the garden, you can get to know what your plants look like. This will help you recognize when something is wrong. Look on the undersides of leaves, too, for any pests that might be hiding there. Keep in mind, not all bugs are bad. And no bug is actually a problem until its population gets above a certain threshold.
Have any questions about this lesson? Email Erin! firstname.lastname@example.org