Planting Into Sand Substrate

Lost my way with fishkeeping, but now looking to get things back up and running. Currently have two 125 litre tanks running with a few fish in and a 180 and a 90 litre tank that are empty, although still have substrate etc in. Gave plants a go but failed miserably. However have been revisiting things over the last couple of months and have come up with a plan.

All the tanks have a sand substrate as i am mad about Corydoras, so as i understand it i will need to use root tabs in the sand to help the plants grow. Also thinking of attaching plants to decorations so will need to use fertilzer for those. My questions at the moment are.

1. If the tank is empty and i put plants in it apart from fertiliser and root tabs, is there anything else i need to add as will be missing fish poop.

2. One set of lights have a adjustable spectrum on them, one of the other is led lights and the two 125 litres are T5 bulbs. Would i be best getting bulbs for plant growth?

3. How long should i keep the lights on for?

I seem to remember  @Matt being knowlegeable but if anyone can help that would be great.

Any help much appreciated.

2. The best lighting for plants has a K rating of 6500. Do the fixed spectrum bulbs have a K rating on the tubes, or even the manufacturer's website? The adjustable light needs red, blue and green. Too much red or blue will encourage algae to grow.

According to the website the K rating is 7500

Well @barneyadi I deserve a right good talking to for not replying sooner!!!

All good advice from @Sue

Only thing I would add really is to ensure the plants have enough depth of sand to root properly and I would also ask what your stocking level is and what you are fertilising the water column with? Dependant on stocking levels you might want a “complete” fertiliser with macro as well as micro nutrients.

Good choice of fert in that it contains potasium which some miss and which often need a boost. It is nitrate and phosphate free.

Nitrate you will know if added to the aquarium through the nitrogen cycle assuming your fish load is high enough there should always be some nitrate available for your plants. You likely also have a nitrate tester to prove/disprove this. 

Phosphate isn’t needed in such high quantities and should be ok (generally) and is added through feeding the fish as it’s found in fish food.

So you can see therefore if your fish stocking levels arnt particularly low (so nitrate and phosphate low), or plant mass especially high (using lots of nitrate and phosphate), then you are on the right tracks

Root tabs - just shove another down at the base of the plant after a few months if you want rapid growth to continue - equally if you’re happy with the size of purge plant etc, don’t bother, they’ll continue to grow, just more slowly.