Maxsea kelp based foliar fertalizer

I have been reading a lot about the kelp based fertilizers.  I have MAXSEA I use as a spray on the leaves of the plants but can I also use it as a straight fertilizer into the soil when mixed with water?? 
 
My 7 pot is doing great, my chocolate scorpion is doing great, my ghost while it has pods is not really doing much at all. Wondering if I can kick it back into growth with some MAXSEA. I am using a very diluted hydroponic solution on all plants about once per month. I noticed the leaves on all plants are a light green, not the dark green they normally have. But like I said above all plants are doing well except the ghost..... suggestions??
 
All 3 plants are grouped together, they get about 7 hours of sun per day, 4 morning sun and 3 of the hot afternoon sun..... the rest of time they are shaded by a big maple tree. 
 
I am in zone 6a.
 
 

pics?

I recommend using your usual fertilizer and then apply kelp extract on a monthly basis. Kelp works because it contains auxins, cytokininins and gibberelins (plant growth hormones and regulators). Ideally, kelp will kick the plant into gear and produce roots which in turn will produce the hormones responsible to top growth. If you use a poor quality or degraded kelp extract you risk producing top growth without the roots to support the plant. If you use kelp too regularly you kick the plant into overdrive and get diminishing returns. Anyways kelp is a great additive as an initial soil amendment for organic growing, as a growth enhancer or to encourage a plant to grow a bit better if conditions aren't ideal- you just have to use it properly alongside good plant culture to get the results you desire.
 
More reading:
 
http://firstrays.com/free-information/feeding-and-watering/fertilizer-information/kelpmax/

Thank you Fish for the response... I did read the link and it is a bit over my head technically but I get the gist of it. 
 
Gorizza, I will work on pics tonight. 
 
 
Thanks for the responses......