Tag Archives: soil health

What’s a Nitrogen Fixer?

Nitrogen fixing plants have a symbiotic relationship with specific bacteria. The bacteria colonize the plant’s roots and pull nitrogen out of the atmosphere. The bacteria uses the nitrogen and then it becomes available to the plant.

Nitrogen fixing plants include most plants in the legume family. They also include certain grasses like buckwheat but legumes are generally the most efficient. 

Why are they important?

Nitrogen is key for plant growth. Plants require it in order to perform photosynthesis. Yellow or pale leaves can be a sign that your soil lacks sufficient nitrogen. Rotating nitrogen-fixing crops through your garden replenishes nutrients in the soil without resorting to using synthetic fertilizers. 

Many nitrogen fixing crops, like those listed below, are used as cover crops or green manures. Like other cover crops they help prevent moisture loss, reduce erosion, and provide habitat for beneficial insects and fungi all while adding nitrogen to the soil. Using cover crops is in investment in soil health.

Nitrogen Fixing Cover Crops

Other legume crops like beans and peas are also nitrogen fixing. Pole beans are grown in the “Three Sisters” garden technique because they help provide nitrogen for the heavy-feeding corn.

Growing Cover Crops

Nitrogen fixing cover crops can be used in different ways. Biennial or perennial crops like clover are often grown for a season or year and then tillled under. This process adds organic matter to the soil and makes the plants’ nitrogen and other nutrients available to your crops. Alternatively winter-kill or annual crops like Sunn Hemp die back on their own and can be used as mulch. As they decompose they add nutrients and organic matter to the soil. 

These nitrogen fixing crops are also perfect for permanent pathways between rows or beds. Clover pathways in particular can be mowed through the summer. The clippings make excellent mulch for the adjacent beds.  

You can find more individual information under individual variety descriptions. 

 

The Importance of Sustainable Soil Management

Your garden harvest starts with healthy soil. How much produce you get, whether your plants are affected by disease, and even how many pests you have can be affected by how you treat your soil. But how you manage your soil can also affect wildlife and the environment.

Algal Blooms

On this blog, we’ve frequently discussed the importance of mulch and cover crops. They are two simple ways to help prevent soil erosion and nutrient runoff. While these effects are obviously bad for your garden they also have more far-reaching consequences. When soil and nutrients erode they contribute to algal blooms in streams, lakes, rivers, and eventually the ocean. 

Algal blooms can be green, red, blue, or brown. They affect both marine and freshwater environments and produce toxins that have a variety of negative effects. The toxins can sicken or kill people and animals, create dead zones in the water, raise treatment costs for drinking water, and hurt industries that depend on clean water. One way we can prevent these algal blooms is to practice good soil management.

Good Soil Practices

Sustainable soil management means using practices that build healthy soil, reduce erosion, and reduce the need for fertilizer, pesticides, and herbicides. They include:

  • Planting cover crops, especially in the fall to prevent erosion and add nutrients and organic matter to the soil.
  • Using mulch around plants whenever possible to prevent erosion, suppress weeds, hold moisture, and add nutrients and organic matter to the soil.  
  • Rotating crops to disrupt disease and pest life cycles and reduce excess nutrients.
  • Reducing soil compaction which helps fungal and insect life in soil thrive. Whenever possible reduce tilling and using equipment. 
  • Providing habitat for beneficial insects like cover crops, mulch, wildflower patches, and insect hotels.

While small gardeners and farmers are not the biggest contributors to this type of pollution every little bit helps. Making these small changes can improve your garden, improve water quality, and help wildlife.

Understanding Soil Tests

If you’ve never had your soil tested you may want to consider it. While soil tests may seem like something more suited to commercial growers than backyard gardeners they’re actually quite simple and affordable. In fact some local extension agencies and/or state colleges offer this service for free. While you can purchase at home soil tests generally having it professionally done is a good place to start. 

Here’s what you can expect from a soil a test and what it will mean for your garden. 

Macronutrients

Primary Nutrients

The following three nutrients are considered the primary nutrients and the probably the most discussed by gardeners.

  • Nitrogen 
  • Phosphorus 
  • Potassium 

Nitrogen is important for plant’s vegetative growth. Phosphorus helps in root and flower development. Potassium promotes vigor. These are found in a variety of commercial fertilizers and homemade garden amendments.

Secondary Nutrients

  • Sulfur 
  • Magnesium
  • Calcium

Calcium helps plants build strong cell walls, magnesium is an important part of chlorophyll, and sulfur is important for the growth of roots and seeds. Just like primary nutrients these secondary nutrients can be purchased in commercial amendments or you can make homemade ones.

Micronutrients/Trace Minerals

Some soil tests will give you the option of testing for micronutrients or trace minerals. These are minerals that plants need in very small amounts. 

  • Boron 
  • Chlorine
  • Copper
  • Iron
  • Manganese
  • Molybdenum
  • Zinc

Unless you suspect a problem testing for these is probably unnecessary. Most soils have enough to keep plants healthy and deficiencies in these minerals aren’t caused by their lack of presence in the soil rather an inability for plants to take up the nutrient because of other problems such as drought stress or incorrect pH. 

These minerals are also typically present in large enough quantities for gardens in any organic fertilizer or other amendments even simple, good quality compost. 

Soil pH Level

Another important part of your soil test is your soil’s pH. pH is the measure of how acidic or alkaline your soil is. It’s an important feature on your soil test as it affects soil nutrient availability and microbe activity. This means that even if a nutrient is in your soil it may still be unavailable to plants do to your soil’s pH.

It’s also worth noting that some crops like blueberries and potatoes prefer more acidic soil than others. 

Amending Your Soil

Once you get your results you can amend your soil as needed. There are a variety of products available commercially or you can use homemade garden amendments like compost and compost tea, manure, coffee grounds, egg shells, pine needles and more. 

You may be able to get personalized recommendations from your local extension agency or soil testing service.

When adding any garden amendment it’s important to thoroughly research its effects on your garden. Certain amendments like oyster shells for calcium can affect your soil’s pH and may affect the availability of other important nutrients. You also want to avoid adding too much of anything to your garden as this can be just as bad as too little. Excess nutrients can also run off into streams and other water bodies causing toxic algae blooms.

11 Free Organic Methods to Add Nutrients to Your Garden

Seedlings

If you start your own transplants at home don’t forget about the nutrients they need. Buying or mixing a good quality potting mix is important to their success. One of my favorite ways to give seedlings a quick boost is to add a bit of compost tea or liquid kelp to their water. I typically use about 5 TBS per gallon of water. 

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