▁v erna ▁that ▁after - ri pen ed ▁into ▁m ature ▁se eds . ▁From ▁ 7 0 % ▁to ▁ 1 0 0 % ▁hum id ity , ▁the ▁se eds ▁ro tt ed ▁from ▁too ▁much ▁expos ure ▁to ▁a ▁mo ist ▁environment . ▁ ▁Cold ▁The ▁cold ▁affect s ▁these ▁plants ▁since ▁they ▁are ▁winter ▁annual ▁plants . ▁When ▁they ▁are ▁exposed ▁to ▁col der ▁temper atures ▁a ▁set ▁of ▁signals ▁is ▁released ▁within ▁the ▁plant ▁in ▁order ▁to ▁surv ive ▁the ▁fro st . ▁In ▁temper ate ▁clim ates ▁such ▁as ▁those ▁where ▁D . ▁v erna ▁is ▁found ▁the ▁plants ▁ce ase ▁their ▁growth ▁in ▁the ▁aut umn ▁when ▁the ▁cool er ▁temper atures ▁arrive ▁and ▁the ▁sun light ▁is ▁less ▁available . ▁This ▁prepar es ▁the ▁plant ▁for ▁season al ▁acc lim ation ▁to ▁the ▁cool er ▁temper atures . ▁When ▁these ▁plants ▁don ' t ▁get ▁the ▁chance ▁to ▁acc lim ate ▁to ▁the ▁cold ▁over ▁an ▁“ aut umn al ▁season ” ▁then ▁their ▁mort ality ▁rate ▁dr ast ically ▁increases . ▁ ▁Light ▁It ▁has ▁been ▁found ▁that ▁these ▁se eds ▁germ inate ▁best ▁when ▁they ▁receive ▁sufficient ▁amounts ▁of ▁water ▁from ▁the ▁surrounding ▁soil , ▁and ▁receive ▁light ▁until ▁they ▁are ▁about ▁ 5 – 7 ▁weeks ▁old , ▁then ▁being ▁buried ▁or ▁covered ▁under ▁the ▁soil , ▁allowing ▁them ▁to ▁grow ▁and ▁m ature . ▁If ▁the ▁se eds ▁are ▁covered ▁before ▁receiving ▁ 5 – 7 ▁weeks ▁of ▁sun light ,