New Vegetable Bed

Asked April 18, 2018, 2:20 PM EDT

Greetings Thank you so much for your service!! My soil tests were returned telling me that my soil was contaminated with lead -- 380 ppm. So I've discarded the old soil and now need to resupply. Can you please advice me regarding the ideal soil mix for growing vegetables? The beds are roughly 10 x 4. Should I use only Leafgro? Or Leafgro + topsoil? Sand? Thanks for any direction you can lend. Kind Regards

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1 Response

You can use the recommendations for raised beds: https://extension.umd.edu/hgic/learn/raised-beds

Should I buy topsoil?

1. Topsoil sales are not regulated. Determine quality of purchased topsoil before it’s delivered. Watch out for soils that are white, gray, or black, smell bad or don’t look or feel like topsoil. Ask the company for soil test reports and information on the origin and quality of the topsoil.

2. Try to locate a business that produces and sells a compost/topsoil mixture (often 70% topsoil; 30% compost). If you purchase topsoil with no added compost you should plan on adding at least 2-inches of compost.

Organic matter

1. What is it: plants and animals that are alive, dead, or in some stage of decomposition. There may be a billion living microorganisms in a teaspoon or compost or soil!

2. Organic matter improves the structure of soils that are high in clay or sand so that roots can better grow and take advantage of available water, air, and nutrients.

3. How much should I add? Fresh organic materials lose more than half their volume by the time they are fully decomposed. The best option, if available, is to add compost to the soil. You need 3 cu. yds. of OM to add a 1 in. layer to 1,000 sq. ft. (8 cu. ft. to cover 100 sq. ft.). 7.5 gallons = 1 cu. ft.; so 12, 5-gallon buckets of compost would cover 100 sq. ft. to a depth of 1-inch.

4. Types of organic matter: composted yard waste (home-made, purchased from your landfill, Leafgro). Mushroom compost is a good garden compost. Well-rotted farm manure added and turned under in the fall is good but can introduce weed seeds. You can increase soil organic matter levels with buried kitchen scraps, cover crops, and yearly additions of compost.

What about potting mix?

1. You can increase your raised bed volume (more rooting area for plants) by adding purchased soilless growing media. These typically contain ingredients such as peat moss, composted bark, perlite, vermiculite, compost, coconut coir. They improve drainage and water holding capacity but are costly and not generally recommended unless the raised bed is set on an impervious surface. In that case, a 50:50 mixture of a good soilless growing medium and compost is recommended.

Poor surface and internal drainage- drainage test. Dig a hole 12 inches deep and 8 inches in diameter.

Fill it with water. Fill it again 12 hours later. All the water should drain out within 2-3 hours. Be prepared to dig up and remove rocks, debris, obstructions you encounter.

Not necessary: weed barrier, rocks, broken pot shards under the raised bed

ECN