The 2019 Soil Kitchen results are now available!
We had a great turnout to our third Soil Kitchen! Gardeners brought us 261 soil samples from all around Austin.
What’s in Your Garden Soil?
What do my METALS numbers mean?
|Soil to Groundwater (the metals can leach from the soil to the groundwater)||Total Soil Combined (includes inhalation, ingestion, dermal, and vegtables consumption pathways)|
|Arsenic||5 ppm||24 ppm|
|Lead||3 ppm||500 ppm*|
*There is no known safe level for ingestion of lead.
- If you have heavy metals below the Soil to Groundwater numbers, in general there is no need to be concerned about lead or heavy metal exposure.
- If your results are between the Soil to Groundwater number and Total Soil Combined, conduct best management practices (BMPs) to minimize lead exposure from vegetable gardens: maintain high pH for fruiting vegetables, keep soil mulched to minimize dust inhalation.
- If your numbers are really close to the Total Soil Combined, then you should consider not growing leafy vegetables or root vegetables.
- If your numbers are above Total Soil Combined, you should consider a raised bed or do not grow a vegetable garden. Place mulch, gravel or paving stones around the raised beds to prevent dust inhalation as you garden.
Best Practices for Gardeners
Have metals in your soil? Or don't know what is in your soil? Try these tips!
- Mix 50 percent compost and other organic amendments to your garden soil to dilute any contaminant concentrations
- Plant in raised beds or containers to separate food crops from contaminated soil
- Locate gardens away from old painted buildings and roads with heavy traffic
- Place landscape fabric between potentially contaminated soil and new, clean soil
- Use paving stones or mulch to control dust from walkways
- Watch over small children to stop them from eating soil through hand-to-mouth play
- Wash hands immediately after gardening and before eating to avoid accidentally consuming soil
- Wear gloves as a barrier between your hands and the soil
- Discard outer leaves of greens, especially from bottom of plants, before washing
- Wash produce well
- Peel vegetables, especially root vegetables, which are in direct contact with soil
Avoid bringing contaminated soil into the home by:
- Cleaning tools, gloves and shoes before bringing them indoors
- Putting soiled clothes in a bag before bringing them indoors
- Washing garden clothes promptly in a separate load
- Rinse excess dirt from crops before bringing them indoors
What about the Soil NUTRIENTS?
If you have high levels of nitrates or phosphorous, your garden may be contributing to groundwater and surface water pollution.
Gardeners might need to add nitrogen fertilizer to their gardens to provide just the right food for their plants. While an addition of nitrogen and phosphorus to the lawn and garden may be necessary, homeowners often use more than what's recommended, and over time this excess nitrogen (over 19 ppm) and phosphorus (over 50 ppm) pollutes water and air. Nitrogen and phosphorus at higher levels causes a loss of certain plant species, death of fish and aquatic organisms, and contamination of drinking water.
Talk to us!
We hope your garden will grow wonderful fruits and vegtables this spring and summer. Send us an e-mail if you think of ways we can improve our 'Soil Kitchen' event. All ideas are welcomed and encouraged: email@example.com