You are testing which fertilizer makes the radishes grow the fastest.
factors you should control: sunlight exposure, water amount, fertilizer amount.
Measure: check the rows of radishes to see how much each row has grown in comparison to the others. Whichever row with the healthiest radishes has the best fertilizer.
When dissolved in water, acids donate hydrogen ions (H+). Hydrogen ions are hydrogen atoms that have lost an electron and now have just a proton, giving them a positive electrical charge. ... If a solution has a high concentration of H+ ions, then it is acidic.