Food Adventures with Connie

Archive for the category “garden”

The Who, What, Where, When, Why, and How of Soil Sampling for Home Fruit and Vegetable Production

Whether establishing a new garden or orchard or managing an existing planting, submitting a soil sample for analysis is an important step in sustainable food production.  The results you obtain from this test will let you know if your soil has an appropriate pH for the crop you want to grow and offer recommendations of amendments necessary for optimal plant growth; they will also let you know if you can cut back on your fertilizer applications which will save you money and may result in greater yield.

handful-of-garden-soil

Who?

Anyone growing fruits or vegetables should collect and submit a soil sample for testing every three to five years, more often if changing production systems or trying to identify the cause of poor plant growth and production.

What?

A soil sample is a composite mixture of multiple sub-samples (10 to 15 should be sufficient for most home plantings).  If your planting contains more than one soil type (different texture, color, drainage, etc.), then you should collect a separate sample of each.

Where?

Sub-samples should be collected randomly across the production area, to a depth of 6 to 8 inches.  In perennial tree and vine crops you may want to collect a second sample as deep as 24 inches if you suspect severe subsoil problems; the root systems of these plants may extend 36 inches or more into the soil.  Keep in mind however that amendments primarily affect just the upper soil layer; nutrients like phosphorus and potassium and amendments for adjusting pH like lime are not very mobile in the soil.  Incorporating these amendments deeper in the soil is not an option for perennial plants because you want to avoid damaging their root systems.

When?

A soil sample can be taken any time the soil is not frozen.  It is best to submit samples in the fall or early spring so you have time to apply any necessary amendments before or early in the next growing season.  Soil test values will vary by season; you will want to collect samples in subsequent years during the same season so results and recommendations can be compared.

For best results, collect samples when the soil is relatively dry rather than after a rain event or irrigation.

Why?

Soil pH and nutrient content have a direct effect on the health and productivity of fruit and vegetable plants.  Submitting soil samples for testing will provide you with recommendations for amendments that can improve your soil quality.

Your results may indicate that you have been applying too much of certain nutrients.  For example, excessive nitrogen in the soil will cause your plants to become excessively vegetative (lush green growth) with a negative effect on fruit yield and quality.  Knowing this will allow you to reduce your fertilizer inputs, and therefore your annual input costs.

How?

soil-probes

Three different soil probes capable of sampling to a depth of 8 inches.

Use a soil probe, auger, spade, or shovel to collect sub-samples from 10 to 15 points across your production area.  Make sure you sample from where the plant root systems are or will be (rather than from walkways, for example).  Mix the sub-samples together in a clean plastic bucket, removing any large stones, vegetation, or other foreign material.  You’ll need about two cups of soil to fill the lab-provided sample container.

soil-auger-peach

Soil sampling in a peach planting using an auger. Samples should be collected where the plant’s roots are located, here at the peach tree’s dripline.

Several labs in Nebraska offer soil testing.  Midwest Laboratories in Omaha and AgSource in Lincoln are two options.  Their websites contain information about requesting a soil sample test kit, which parameters they test for, and when you can expect to receive your results.  The test will cost approximately $25 per sample.

Next Steps

Your soil test results will contain recommendations for soil amendments based on the garden or orchard crops you indicate on the sample submission form.  If you have questions about interpreting your test results or which soil amendments will best meet the needs of your site and production system, contact your local Nebraska Extension office.

Most fruit and vegetable plants prefer an acidic soil pH.  If your test results indicate that the soil’s pH is too high, elemental sulfur can be used to lower it.  Just keep in mind that Nebraska’s clay soils have a high buffering capacity which means that their pH will immediately begin to rise after you add sulfur.  To maintain the desired pH you may need to add sulfur every year or two.

For more information about managing soil and nutrients for vegetable production check out UNL’s Fertilizers for Vegetables in Home Gardens. The Midwest Home Fruit Production Guide is an excellent source of information about fruit production, including recommended fertilizer rates.

Handful of garden soil photo via Jing, https://pixabay.com/en/soil-hand-farm-garden-fertilizer-766281/, CC0 Public Domain.

The Beauty of the Garden

I love working in the garden this time of year, whether weeding or scouting for insects and diseases.  Yesterday morning was particularly pleasant weather-wise, the pumpkins, watermelons, and cantaloupes are all in bloom, the aroma of fresh tilled soil was in the air, and a variety of pollinators were busy buzzing around.  I encourage you to take the time to experience a garden with all your senses, and share it with young people in your life.  It will feed your body as well as your soul.

Thoreau quote over cantaloupe flowers

How to Grow Bindweed (and what to do if you don’t want to grow it)

If you garden, chances are that you have encountered bindweed (AKA Creeping Jenny). You can mow it, pull it, and cultivate around your vegetable plants all season and yet every day seemingly find new bindweed plants. Have you ever wondered if your control strategies are actually helping the bindweed to grow?


The Plant

Penn State Extension (see Field Bindweed link below) offers a good description of bindweed: “A vinelike perennial, field bindweed belongs to the morning glory family (Convolvulaceae). Its slender stems can form dense tangled mats up to 10 feet (3 m) across, and climb by wrapping around nearby plants and objects.”

In case you’ve never seen bindweed before, here’s what it looks like. Notice the leaves shaped like blunt arrowheads and the easily severed taproot. This taproot may extend many feet into the soil and can survive soil temperatures as low at 20°F which means that it can come back year after year from the roots.

small bindweed plant showing leaves and taproot

Figure 1. Typical bindweed leaf shape and taproot (click to zoom).

This taproot generates many side roots extending one to three feet away from the taproot. These side roots produce buds underground that can develop into new plants. That’s right, if you manually remove bindweed plants as shown above, the side roots left in the soil are capable of becoming new plants.

If, rather than pulling weeds, you till between the rows in your garden every few weeks you may be chopping up these roots.  And root pieces as short as two inches can form new plants! (I learned that mistake the hard way managing a community garden in Wyoming.)

If the bindweed is allowed to grow to maturity it will produce white or pink funnel shaped flowers that bloom from June through September. Typical of species in the morning glory family, the flowers open during the early morning hours and then close later in the day.

I think the flowers are kind of pretty (plant nerd here), but if these flowers are left unchallenged, they will produce seeds. One bindweed plant may produce as many as 550 seeds that can remain viable in your soil for 20 years! So, in addition to controlling bindweed in your garden, you need to control bindweed around the garden, in surrounding fields and ditches, and along fence lines if you want to prevent the production and spread of seeds.

Bindweed is found throughout the United States in all kinds of soils, so it’s not picky about growing conditions. It is also drought tolerant and when water is limited it will outcompete most of your garden plants.

young bindweed plant much larger than other young weeds

Figure 2. This field was plowed two weeks ago. See the difference between the growth of the bindweed and other common weeds?


Controlling Bindweed With or Without Chemicals

Bindweed is sensitive to shade, so if you can manually remove it early in the season fast growing garden crops may be able to help suppress its growth. However, if the bindweed is more than a year old, with a well-established root system, shading won’t even slow it down. It will even grow several feet under plastic or landscape fabric to emerge from the holes you cut for your vegetable plants.

Effective non-chemical control requires a multi-pronged approach including:

  1. Disruption of carbohydrate storage by deep tillage of the root system (so unfortunately no till is not a good choice if you’re trying to control bindweed without chemicals)
  2. Competition for light from other plants (i.e. vegetable plants, cover crops, perennial grasses or forages)
  3. Prevention of seed production (mowing will not reduce bindweed infestations, but can reduce seed production if timed to prevent flowering)
  4. Constant manual removal of top growth (yes, that means getting on your hands and knees and gently pulling young bindweed plants before they have a chance to establish)

Chickens are another non-chemical control option. They eat bindweed leaves and stems and expose crowns and roots, further depleting root carbohydrate reserves. However, chickens will be just as happy to eat your vegetable plants and pose a food safety risk if allowed in the garden within 120 days of harvest, so they should only be used after you’ve finished harvesting your crops for the season.

If you’ve tried all of the above and still can’t seem to get your bindweed under control you may want to consider chemical options. Contact herbicides can kill back the aboveground growth (and may be useful for preventing seed production), but their effects are only temporary because the plant will just send up new shoots from the root buds.

Systemic herbicides are more effective as they are translocated throughout the plant. Systemic herbicides should be applied when bindweed is in bud or the early bloom stage because that’s when root reserves are lowest and translocation from the leaves to the roots is most active.

Unfortunately bindweed is a broadleaf plant like most of the vegetables in the garden, so if you decide to use herbicides you must be careful to avoid damaging your crops at the same time. One way to accomplish this is to place a rubber glove on your hand and wear a cotton glove or sock over it that you can spray or dip into a small container of systemic herbicide like glyphosate (Roundup) or 2,4-D, and then carefully wipe it on the leaves of the bindweed.  This procedure will need to be repeated about every 10 days until the bindweed dies.

Regardless of the herbicide chosen, chemical control is most effective when combined with the non-chemical control options described above.


For more information:

Bindweed Identification and Control Options for Organic Production

Field Bindweed

Field Bindweed Control Alternatives

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