Is my soil safe to grow vegetables?

If you want gorgeous, tasty vegetables, there are a few things you need to reach that goal. Access to water and plenty of sunlight allows your vegetables to grow big and delicious. Another vital ingredient for healthy vegetables is nutrient-rich, well-drained soil. 

However, some issues can be present in the soil that may make it unsuitable for vegetable growth. These issues, such as lack of nitrogen or poor drainage, can be easily improved. 

Unfortunately, problems like high levels of heavy metals can harm those who consume vegetables grown in such soil. 

Concerns about soil safety are common, particularly in cities. These concerns exist due to the view that some cities struggle to provide clean water and air. In these cities, soil can be contaminated by heavy metals such as lead.

Soil samples being taken from the ground for testing

Is lead in soil dangerous?

Of all of the contaminants found in garden soil, lead is one of the most common and one of the most harmful to the consumer’s health. Lead in soil is most dangerous when found at high levels. 

Exposure to lead can cause neurological issues, kidney damage, anemia, and brain damage. 

Lead exposure is most harmful to children, fetuses, and pregnant women.

What other toxins are considered soil contaminants?

In addition to lead, there are a few other common contaminants that can be harmful to your health. These toxins can include lead, other heavy metals, pesticides, and arsenic. Generally, these substances exist in smaller amounts in soil than lead.

Do vegetables absorb toxins from the soil? 

Many people have concerns about contamination in the soil, causing contamination in the vegetables grown in that soil. While plants absorb some contaminants from the soil, these levels are often not high enough to be harmful to the consumer.  

Even though the risk of harm from consumption of these vegetables is low, it is still a good idea to reduce exposure in the actual act of gardening. You can take measures to reduce your exposure to lead and other contaminants in the garden. 

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How do different plants react to soil issues?

Certain vegetables are likely to absorb more harmful contaminants, such as lead, which can be absorbed by the consumer. These vegetables include green leafy vegetables or root vegetables. 

Growing vegetables in contaminated soil are mostly harmful if you do not wash your produce.  

As far as the actual growth of plants in contaminated soil, it can be damaged by soil contamination. Planting trees in contaminated soil can lead to slow growth. Heavy metals can cause the soil microbiome to behave differently than the microbiome of uncontaminated soil. 

Some plants are useful for cleaning up toxins. The process that these plants perform is phytoremediation. Only certain varieties of plants do well in this context. Some of these plants include mustard greens, poplars, willows, sunflowers, and water hyacinth. 

Each of these plants can perform slightly different tasks, from the sunflower absorbing radiation to mustard greens being able to absorb lead. Willows and water hyacinth can both effectively remove heavy metals from the soil. 

How do I know if my garden soil is safe?

The most effective way to know if the soil is safe for a garden is by performing tests on your soil. There are many ways to test soil for lead and other heavy metals. Look for reliable tests that allow you to collect samples of your soil. 

These tests may look for levels of metals such as cadmium, chromium, copper, nickel, and zinc. 

You can send in samples of your soil to an EPA accredited lab. In some areas of the world, you can bring your soil to a soil screening event. When gathering samples from your yard, ensure you collect them from several different parts of your yard. 

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Doing this will ensure you have a more comprehensive idea of the amount of lead throughout your whole yard.   

Take the results you get back and see how they compare to the average amount of those metals in the soil near you. Check if the number of metals in your soil is within safe bounds. 

When testing your soil, it is useful to know of possible sources of contamination. Growing a garden on or near a present or former industrial site can lead to contamination. Gas stations, industrial sites, and dry cleaners can all add chemicals to the environment. 

You should also note if your garden is near a landfill, highway, parking lot, or junkyard. A garden planted on the site of a demolished house or garage may also offer exposure to chemicals or other contamination. 

Gardens near cropland or agricultural areas can also get contaminated with water run-off from fertilizers and pesticides. 

What are acceptable levels of heavy metals in soil?

Even though the ideal amount of heavy metals in a garden’s soil is none, it is almost impossible to find a space without a bit of contamination. Therefore, it is necessary to determine safe levels of lead exposure. 

When looking at amounts of heavy metals and other contaminants in soil, these amounts are measured in parts per million (PPM). When you get your results back, you can decide what kinds of crops you want to grow, based on the amount of lead concentration. 

A concentration of about 200 ppm or under is fairly safe for growing vegetables and spending time in the garden. However, if the level of lead is between 200 and 350 ppm you can grow non-root vegetables. 

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Some gardening is safe between 350 and 650 ppm, however, you need to be highly careful about the specific vegetables you grow. Anything above 800 ppm is likely not suited to gardening. 

Other heavy metals and contaminants may have different safe levels than lead. Cadmium and arsenic are two substances that can cause harm in large amounts. 

What do I do if my soil is not safe for growing vegetables?

If you discover that your soil contains high levels of lead or heavy toxins, you should know that there are a few ways to reduce the levels of harmful chemicals. Unfortunately, it is not possible to fully remove all soil contamination instantly. 

Providing your garden with plenty of rich compost and aiming for a neutral soil pH are a few ways you can reduce lead and other soil contaminants. You can also add mulch, fresh soil, and other materials to reduce the number of contaminants. 

If you can determine which parts of your garden have the highest contamination levels, you can restrict access to those areas, so the rest of your garden does not become more contaminated. 

You can take several measures to keep contamination from spreading if you are exposed in the garden. Start by wearing gloves while gardening and not wearing your shoes inside after gardening in them. 

There are several measures you can take to keep contamination from spreading if you are exposed in the garden. Start by wearing gloves while gardening and not wearing your shoes inside after gardening in them. 

If you do grow some vegetables, thoroughly clean them before consuming them.