if you are going to use ffhf I wouldnt worry about it being to hot. started 20 or so straight into the soil for germination in ffhf never had any issues with to hot. now I use promix hp way better drainage no nutes in it so I have full control dont have to worry about it being to hot. Just start my nutes in 7 to 10 days at 1/4 strength work great for the 10 or so plants I have started so far.