Tree Irrigation Rates

[SLOBuds]

I'm going to plant a bunch of trees (50 or so) on my farm. These will be landscape trees for shade and appearance only. Planted as saplings this winter.

I can't seem to find any online resources to tell me how much water they will need. I'll have them on timed drip but I need to find somewhere that shows me how much water is needed.

Any ideas?

Thanks,
Martin Petersen

[Fawteen]

The standard guideline is 1 inch per week over the area above the root ball. You can do the math to convert that to gallons and base your timing on the rated flow of the drip emitter.

[SLOBuds]

Thanks Fawteen.

How do I convert inches to gallons? (Sorry [img]/forums/images/icons/smile.gif[/img] )

And how do I handle variations in heat? Meaning that our weather (Central California) varies from chilly in the winter to quite hot in the summer.

Winter will average mid-50s, with some high 40s. Summer will average low-90s up to quite a few days of low/mid-100s.

Low humidity all year round.

What type of adjustments do you think I should make for these temperatures and conditions as the seasons pass?

Thanks again,
Martin

[Gatorboy]

While they are small, if you get 5 rain free days in a row, then water them.

[Fawteen]

Heh, heh, heh, I KNEW that question would come up.

Okay, it's just a little math, don't be scared now... [img]/forums/images/icons/grin.gif[/img]

Let's assume the rootball is 3 feet in diameter. Area of a circle is pi times radius squared or 3.14 times 324 (18" squared) gives us 1017 square inches. At a depth of 1" that gives us 1017 cubic inches. A gallon is roughly 269 cubic inches, so it would take 3 and 3/4 gallons to cover a circle 3 feet in diameter to a depth of 1".

Now all you need to know is how many gallons per hour your drip emitter puts out, and run it long enough to put out 4 gallons once a week.

[Fawteen]

Sorry, I got interrupted in mid-post for a fire call, forgot to answer your questions about variations.

Anyway... an inch a week should be sufficient, but if the ground gets too dry you could double that no problem. I wouldn't worry about adjusting for the winter temperatures.

DO mulch the area, it'll help retain moisture. DON'T mulch up against the trunk (provides a way for boring insects to get at the bark) and don't OVER mulch, it compacts and blocks air to the roots. Don't use fabric mulch for the same reason. Ground bark is the best all-around mulch for this application.

[SLOBuds]

Thanks! Both of those answers give excellent guidelines and other good tips regarding mulch.

And the math isn't scary at all. Do you use the tree's dripline to estimate rootball size?

It will be very easy to simply build a table that has various rootball sizes and their associated gallonage. Then 2x that for July, August, September.

I'm kind of assuming that we can further adjust this by obtaining added detail for each species. For instance, we are going to take a shot at growing Giant Sequoias out there which are documented as needing plenty of water. So we could add a factor to give our Sequoias 1.5x the computed gallonage, as an example.

Thanks again for the info. It's great!

Martin

[Gatorboy]

Fawteen,

It's a good idea NOT to change the title of threads. When looking at the posts made in the last X hours, it appears as it's a brand new thread.

[Fawteen]

Yes, generally speaking the dripline is a good standard to use when estimating the rootball for watering purposes.

Also, a fudge factor for particularly thirsty trees is a good idea.

[Fawteen]

Re: Renaming threads...Ooops, sorry, didn't realize that.