Agriculture Reference
In-Depth Information
The necessity of adding water to the substratum after planting depends on the species, seed size, and
the germination capability of the lot. For example, legumes imbibe more than monocots, larger seeds more
than small seeds, and rapidly germinating species more than slow germinating ones. Addition of water may
be necessary if the ambient relative humidity falls below about 95%; thus great care must be taken to ensure
that the methods and equipment used will maintain this value. Whether additional water may be needed
depends largely on the kind of germinator used.
The AOSA rules identify the following acceptable substrata for germinating seeds: blotters or paper
towels, sand or soil, ilter paper or creped cellulose paper.
blotters
Germination blotters are used primarily for small seeded species and those requiring light. They should
weigh 275 lb per 500 sheets of size 25 x 40 in, have a pH of 6.5 to 7.5, an ash content not exceeding 1%,
sulides and other toxic chemicals below 2 ppm, and a maximum of 5.0% moisture. The AOSA rules rec-
ognize three ways for testing in or on blotters (Fig. 5.2): B = between blotters in which a single blotter is
folded and the seeds placed between the upper and lower folds; TB = top of blotters in which the seeds are
placed directly on top of the blotter. If drying of the blotters is excessive, two blotter thicknesses will pro-
vide moisture over a longer period than a single blotter; RB = blotters with raised covers in which the edges
of a single blotter are folded upwards to form a good support for the upper fold which serves as a cover. This
prevents the top of the cover from making direct contact with the seeds on the lower fold.
Figure 5.2. The recognized AOSA methods for germination testing seeds on blotters: B=between blotters,
TB=top of blotters in which seeds are placed directly on top of one or more layers of blotter and RB=raised
blotters in which single blotter is folded and seeds placed between the upper and lower folds.
