Messages posted to thread:

Rob MacLaren03-Jan-07 12:37 AM EST 4b   
Michelle.L.06-Jan-07 01:37 AM EST 5a   
PatA06-Jan-07 05:06 PM EST 3   

Subject: Cedar Hedge and "toxic proximity"?
From: Rob MacLaren
Zone: 4b
Date: 03-Jan-07 12:37 AM EST

We live in Merritt on the clay bench above the lower town. The back yard of our home is surrounded by 15'- 18' cedar hedges. We learned recently, (from the December 06 GardenWise issue) that cedar hedges exude a substance that inhibits growth of plants nearby. The question to you all is; Given the height of our hedges, what distance from the hedge is "toxic"? We are trying to replan our back yard and wish to take this into consideration. The other question we have relates to addition of Nitrogen to our soil. We had the soil professionally tested in our back in late last growing season and it was indicated that our soil was desperately low in Nitrogen. It came in at "3" with P at >60 and K at 320 and S at 20. The PH at the time was 8.0 with Organic Matter at 4.4 and EC at 0.95 The lab told us to add N at a rate of ~5 pounds/1000 sq ft.. I have 50 lb bags of 34-0-0. The suggestion was that we also add gypsum at 25 lbs/1000 sq ft. before the growing season. This was to aleviate the rather high PH. The question- given the low N, how many times during the year do I need to add the 5 lbs of 34-0-0? And for how many years to bring it back. Did the Cedars have something to do with it? HELP!!!

Subject: RE: Nitrogen lacking!!!
From: Michelle.L.
Zone: 5a
Date: 06-Jan-07 01:37 AM EST

Hi Rob, Wish i had some answers for you, i think your best bet would be to ask the experts!! Why don't you log on to the Live Chat on this website on Sundays? For you in Merritt it would start at 10:00 a.m.

Subject: RE: Nitrogen lacking!!!
From: PatA
Zone: 3
Date: 06-Jan-07 05:06 PM EST

Hi Rob

See my note to Michelle on allelopathy "Impossible area for growing anything" thread.

As far as your soil testing goes... Yup you got it. The cedars had everything to do with your nitrogen depletion and so would any lawn grass. Nitrogen is a nutrient readily used up by plants and washed away by rain (in your area not likely) or heavy watering. You should add the 34-0-0 every spring before growing season AND suppliment with a good quality water soluble evergreen fertilizer every month until August. Plant Prod 30-10-10 is a good one but there are other brands too.

Gypsum is a great additive for clay soils as it helps bind with the salts (your EC was a bit high) and some what breaks up clay soil so it doesn't seem to be so hard BUT it doesn't lower PH on it's own. See website below for more info.

Aluminum sulfate, and water soluble evergreen fertilizer will help. Add aluminum sulfate at the same time as the Nitrogen 34-0-0. The water soluble fertilizer adds a little sulfur everytime so it lowers the PH too.

So the long and the short of it is... Nitrogen, Gypsum and Aluminum Sulfate every spring, and around your cedar hedge use 30-10-10 water soluble once a month for the spring and summer. Repeat every year.

You can retest your soil with a home test kit available at garden centres. Do this every spring before you add ammendments so you keep track of how your soil is doing. Just a note, if your tap water is high in salts (EC above 0.50) use distilled water for your tests and try to accumulate as much rain water as you can to use in the garden.

Hey and tune in to Art, Sunday on LiveChat. He is one of the best.

Hope some of this helps - Pat

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