Nasturtiums - starting indoors

May have started them toooo early indoors in 3" pots and in compost that is toooo rich. They are now 4 inches tall! Any suggestions? Can they be clipped back? Should I repot in plain soil? I gather if they are in soil that is too rich they produce lots of vine, but no flowers. Many thanks.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

Site Timeline is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.