Planted tanks split into two paradigms: low-tech (no CO2 injection, lower light, slow growth, easy maintenance) and high-tech (pressurized CO2, high light, dosed fertilizers, aggressive growth, weekly trimming). Decide which paradigm you're building before buying anything.
Low-tech: Anubias, Java fern, crypts, vallisneria, swords. 30-50 PAR at substrate, no CO2, gentle dosing. High-tech: stem plants, carpeting plants, demanding species. 100-150+ PAR, pressurized CO2, EI dosing, weekly trims.
Low-tech: inert substrate (sand, gravel) + root tabs for crypts/swords. High-tech: active aquasoil (Fluval Stratum, ADA Amazonia, UNS Controsoil) - these substrates buffer pH down and provide nutrients for 12-18 months before replacement.
Low-tech: any reasonable aquarium LED at 30-50 PAR. High-tech: dedicated planted-tank LED (Twinstar, Chihiros WRGB, Fluval Plant 3.0). Photoperiod 6-8 hours initially, ramp to 8-10 hours after the tank balances.
Place rooted plants (crypts, swords, val) first in the substrate. Attach rhizome plants (Anubias, Java fern, Buce) to wood/stone with thread or super glue gel. Stem plants go in last - bunch and plant in groups of 5-7 stems.
Pressurized CO2 system: 5-lb tank ($80-150), regulator with solenoid ($60-200), drop checker ($10), diffuser ($20-100). Target 25-30 ppm during the photoperiod. Drop checker should read lime green.
Low-tech: weekly dose of all-in-one liquid (Easy Green, Tropica Premium) - 1ml per 10 gallons. High-tech EI dosing: KNO3, KH2PO4, K2SO4, CSM+B with iron, alternating macros and micros throughout the week.
Most plants melt (lose leaves) when transitioning from emergent (above-water) culture to submerged. Tissue-culture plants almost always melt. Trim melted leaves and wait 4-8 weeks for submerged-form regrowth.
Cycle the tank with plants alone for 2-4 weeks before adding fish. Plants outcompete algae for nutrients during this window and the system stabilizes. Then introduce livestock.