Between broken pipes, seized pumps, and clogged lines, it can seem like a full-time job just to keep the water flowing on your hemp fields. And with the infinite amount of soil types and weather patterns out there, there is absolutely no 'one size fits all' when it comes to irrigation. That said, here are some basics that we follow.
Initially we water our fields for 24 hours before planting. Our next watering is usually about a week after plants are in the ground, but we sometimes give a light watering earlier if the root balls dry out. Observation is essential and we do our best to keep the soil moist, but not wet. Our early summer watering schedule is usually about once a week, but we like to survey our fields with moisture meters to make sure we aren't missing out on any areas.
During the peak of vegetative growth and in the heat of the summer we water up to two times per week and give each plant up to two gallons per watering. This is at absolute peak and for much of the season it's half that. If you are growing in sandy, well-draining soil, you may find yourself doing this throughout the season. If you are growing on soil that doesn't drain well, or are in a land of mild daytime high temps and summer rains, you may never need to water this much. The amount of variables is never ending.
Field surveys and weather forecasts are the only clues we get. If 100+ degree weather is in the forecast we know to prepare to water more, but if it's going to rain we slow down. We watch the plants. If we see them droop we know we've either under-watered or over-watered. That's right, over-watered plants sag. Most importantly, we try to find the happy medium. Over-watering causes stress as well as root issues such as pythium rot. Under-watering slows growth. With both stressors, they can increase your risk of hermaphroditism.
The challenge is finding the middle ground.
We use these guys for most of our irrigation supplies, and their resources are worth a read. Check out Drip Depot.