Growth stunt

what up imma first time grower, kinda did the steps got seed started the degermination once they cracked i planted them in pre soiled cubes after about a week they were about 2 inches everything as lookin good but im starting to feel like they are starting to grow in slow motion its been 2 and a half weeks now and just barely breaking about 2 and a half inches. how can i speed up the grow process ?
 
Top