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Name: Joe
Status: student
Grade: other
Location: Outside U.S.
Country: United Kingdom
Date: Fall 2010

I am planning an experiment to see whether as a radish seeds exposure to acid increases, it's germination rate decreases. In order to ensure the mineral content of whatever I germinate my seeds in is the same, what would you recommend growing my seeds in, as using a soil will provide too many variables!


You could grow your radishes hydroponically. Hydroponics (From the Greek words hydro, water and ponos, labor) is a method of growing plants using mineral nutrient solutions, in water, without soil.

That way you would have absolute positive control over the content of your nutrients.

Sincere regards,

Mike Stewart

You could try perlite for your seed germination experiment:

Anthony R. Brach, PhD
Missouri Botanical Garden
c/o Harvard University Herbaria

Plants absorb essential nutrients as inorganic ions (positively or negatively charged atoms or molecules) in water. Soil merely acts as a reservoir or receptacle for the water and is not directly essential to the plant’s growth. It is the mineral nutrients in the soil that dissolve into the plant’s water supply. So in essence all a plant really needs is mineral-rich water supply.

Hydroponics (Greek for working water) is a method of growing plants using mineral nutrient solutions in water without soil. Plants may be grown with their roots directly in the mineral solution or in an inert medium such as aquarium gravel, marbles or glass pebbles. Hydroponic solutions allow nutrient levels as well as pH levels to be controlled. Hydroponic nutrient solutions can be found at local gardening centers or plant nurseries. Adjusting pH levels in nutrient solutions is simple. Chemicals such as phosphoric acid (to lower pH) and potassium hydroxide (to raise pH) are safe and can also be found at gardening centers.

Dana Clark

You can obtain thoroughly washed sand from a fish or pet store. Check the pH of a slurry of sand and water and wash it again with distilled water. The pH will still be a little on the acid side due to dissolved CO2, but you can't really avoid that very easily. You can minimize further absorption of CO2 by keeping the containers covered with "plastic wrap". You were right on target to avoid using a soil.

Vince Calder

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