A question for the SIP experts about how to fertilize SIPs. I am wondering if SIPs are fertilized like normal pot plants or if they need special treatment.

For example, should I use solid or liquid fertilizers?
Organic or synthetic?
On the soil or in the reservoir?
Full strength or diluted/reduced?

Thank you

I had my SIPs on one gallon/m drip irrigation for 15 min three time per day from top. I used slow release Osmocote for flower and Vegetables directly into the soil. This year I even added some organic turkey compost to the soil. The rain water also helps.
After seeing a member's post and in order to avoid overwatering, I intend to reduce irrigation to 10 min three times per day and see how it goes. The bottom of container acts as a reservoir.

You asked a question where you will get a wide range of responses. It really depends on what works for you and how you prepare your pots. I would say try Bill's method and modify to your liking.

Me.? I don't cover the top of my trees. So, I use synthetic and organic. I use liquid and dry. I mix liquid fertilizer with water and pour it straight into the reservoir.

Thanks a lot guys.

Yes, I suspected that too, but thought it's still interesting to see who does what and perhaps get a head start and also avoid some fatal mistakes.

I'm making my first SIP now just in time for Spring. I'm also going with an open top.

I sprinkle Osmocote to my plants near the drip.
If you want to put fertilizer in the tank then 1.5-2.0mS is OK. Here some folks set to 3.5mS. I'd rather go with 2.0 :)

But for me..... there are fig trees in various size in my site so I'd rather put fertilizer on the spot instead of in the tank.