Buy a meter. I have an apogee but I have compared it to the soil moisture/ light meter combo I have($10) and it works well enough up to around 1000ppfd. After that the readings are way off. But that’s more than the plants can handle without CO2.
Buy a meter. I have an apogee but I have compared it to the soil moisture/ light meter combo I have($10) and it works well enough up to around 1000ppfd. After that the readings are way off. But that’s more than the plants can handle without CO2.