The experiments indicate that clay pots are superior, as a general rule, to composition pots, paper bands or flats as a growing medium for vegetable plants. If the plants in these substitute containers, however, are watered, about every week or 10 days with a solution of nitrate of soda, sulfate of ammonia or any other nitrogenous fertilizer at the rate of 1 ounce to 1 gallon of water, plants equal to those produced in clay pots are possible. A few species may do as well without nitrates; cabbage plants grown in peat pots were slightly better than those in clay pots even without nitrates. Wood veneer bands were superior to paper bands except where sodium nitrate solution was applied to the plants in the paper bands. Nitrate applications given too freely and too often may result in producing plants with soft, succulent growth.
If plants are sensitive to acid soils, it is well to neutralize the acidity of the peat pots by soaking in lime water for at least 24 hours. Liming is not so essential where nitrates are used. The pulp pots and pulp planting pots are nearly neutral in reaction and do not require liming.
Haber, E. S.
"The effect of various containers on the growth of vegetable plants,"
Bulletin: Vol. 24
, Article 1.
Available at: https://lib.dr.iastate.edu/bulletin/vol24/iss279/1