Watering needs for large conifers

9 years ago

We recently transplanted an assortment of large conifers (14' Concolors and Norway Spruce as well as a couple of 10' Serbian) and we're confused about all the different info out there about how much to water.

Some people say once or twice a week of a thorough soaking is good while some websites say to use up to 2 gallons per caliper inch per day on the trees. I pasted a set of instructions from that particular website below:

"For trees over a 4 inch caliper:
-Daily for six weeks - Depending on temperature and wind, apply 1-2 gallons per inch of trunk diameter.

-Every other day for five months - Depending on temperature and wind, apply 2-4 gallons per inch of trunk diameter.

-Weekly until established (four or more seasons)"

It does go on to say not to oversaturate a site with clay soil (which we have) but still unsure about how much and how often to water. The trees vary in caliper size from 4.5" to 7" and I put in an irrigation system with varying emitter sizes that I can adjust. So for my 7" caliper tree I put in a 5 gallons per hour emitter alongside two 2 gph emitters. My only problem is figuring out how much to use them.

Also, Ive noticed that many of the spruce are browning in the center but am assuming that's just from transplant shock (we transplanted them about 3 weeks ago) and not overwatering.

Any advice would be great. How many gallons per diameter size? How often? The were planted on a 25 degree slope, if that helps.

Comments (3)

PRO
Whitelacey
9 years ago
A general rule-of-thumb- for any plant is to water well and then stop until the soil is just moist. Repeat until well established. There is an oxygen exchange which roots perform that is vital to the life of the tree. If the soil is saturated, as clay soil will be if you water every day, there will be no air in the pores of the soil and the roots will not be able to do their job. Your tree will drown.

When growing anything, the key is to try to emulate its natural environment. It's rare to have a daily rain anywhere so a daily watering is not necessary, Just water well and deeply. This will also encourage the roots to grow deeply as they seek the deeper, moist soil.

If they are on a hill, I would water slowly to ensure that the water is percolating to the plant's roots.

I, too, have soil that is mostly clay. Like a junker car, you just have to know a few tricks to make it behave!

Linda
ken_adrian Adrian MI cold Z5
9 years ago
where are you.

whats the base soil ..

take a hand trowel and dig a small hole at the periphery of that planted.. AND FIND OUT IF ITS WET OR DRY ...

it is so dependent on your soil.. that no one can tell you.. with any authority.. how many gals.. nor how many hours on irrigation etc ... its an art.. not a science ...

they were huge transplants... i presume done professionally .. if so.. do what the seller tells you.. to maintain your warranty ...

see link re: watering

ken

ps: like a dozen other posts on this page.. interior yellowing is normal this time of year.. and increased by transplant ...

Here is a link that might be useful: link
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scotjute Z8
9 years ago
I water at rate of 10 gal per inch of caliber once a week from May to Sept down here in Z8 hot and dry Tx. On newly planted trees would water twice a week for 30 - 45 days and then drop to once a week. My soil is blackland clay topsoil with underlying caliche (limestone and clay).
Everything I plant is 2" caliber or smaller. Usually in 5 gal. pots but sometimes 1o or 15 gal. size.
Planting trees the size you are talking about takes a lot of water. Believe in thoro soaking once or twice a week vs tiny watering everyday. ken had some good points.
Good luck.