Welcome to the forum and allow me to comment on what you got going here. Hopefully my two cents will stop you from experiencing pain and suffering down the way that the majority of us felt when switching from being a reefer to an aquatic farmer. I'm going to take your post one point at a time and explain how/what I would do in order to avoid hiccups. I have no doubt that this will churn up the waters and get a bunch of advice coming in from all over the forum.
Pretty much what I'm going to do is go down your shopping list and look for possible issues that I can help you avoid.
I know that you're going to line the bottom of your tank with your potting mix and then cap it with your sand but you can expect to have some possible algae issues right out of the gate because you are going to have an abundance of free-floating nutrients in your water and unless you plant very heavily (this is important) you aren't going to have the plant biomass required to absorb all of the nutrients. Now if you plant heavily, and I strongly suggest that you do, there is the issue with nutrient bonding for uptake. If all of your plants have all the nutrients they require accept Co2 you're not going to have the uptake required and this is going to lead to algae also. A better way to look at this is think about your salt water/reef tank... imagine trying to grow your LPS/SPS without managing your calcium, Mg, or carbonates. It just isn't going to happen because these elements are key to allowing your reef to flourish. Even though the freshwater planted tank is easier (some would disagree) Co2 is the only nutrient that is truely required to ensure constant nutrient uptake and plant growth and without it algae will again grab a foothold and most likely take over. Worst case scenario with miracle grow is that with that many nutrients in the water you will probably be hit with green water right out of the gate. However, I'm not a dirt guy and I'll let someone who has more experience chime in on that.
Driftwood that has been harvested needs to be boiled and cured prior to entering your tank or your inviting parasitic issues. There are tutorials online regarding numerous methods used to cure driftwood. Put in the time and research and find one that works for you. You may also see white fuzz on your driftwood when it gets put into your tank.. not to worry this will go away in due time without treatment. I refer to this as a driftwood cycle but its completely fine.
Setting the tank up dry prior to filling it with water is a great idea and one that a lot of us wish we would of done but live and learn hehe. Two points to look at when taking this approach though come down to common sense really. Make sure that the plants you are using have an emersed/immersed form and don't forget that when you fill the tank with water that there will be a die off period while these plants transform to their submerged form.
Your lights are fine for intensity but I didn't see a kelvin rating on the container. For maximum growth make sure you're rocking somewhere between 6500 and 10000 for good growth AND back those lights off of the tank. You will not want the lights as close to the tank as you have shown in the picture. Having your lights that close will also contribute to our on-going algae battle that you're going to be fighting without Co2. Plants, even high light plants can grow in a lot less light than we seem to think is considered high light and this is all possible because of the efficiency of today's bulbs BUT you do not need to mirror the light intensity required by a salt water reef tank... not even close. A single bulb in your fixture will feed that tank with enough light for a low-tech tank.
Lastly, get rid of the glass lid and make a DIY screen. There is a link in my signature or just click here
to see how to make them. The reason for the glass removal is that you are going to get tired of cleaning it, proper light coverage is going to be skewed once a bunch of gunk gets on it, and a screen will lower the light intensity therefore cutting down on the chance of getting algae.
In summation here:
With light less is more. Get used to Co2 because its a staple of any successful planted tank. Read up on proper low-tech methodology or get cozy with the EI dosing method. All in all, have a good time with it and for the love of god give us a journal!
Sorry if this is hard to follow and for any typos you may see.
Cheers from Austin,