Raised beds- Fall preparation

[Ed of Somis]

I am expanding my new (2015) raised beds this Fall. This summer my results were so-so...but I expected that because my beds are not fully amended/settled yet. Two questions for you "more experienced" raised bed people: 1. Since my native soil is heavy clay...I plan to soak/rototill and amend as deep as I can (maybe 6-10 inches). Does this work? 2. I plan on amending good topsoil with manure, alfalpha pellets, and compost bags to enrich my backfilling medium. Does that sound right? My frames are 2"x12" boards. Thanks for any advice/ideas. Ed of Somis

[Ricky Shaw]

My main malfunction on new beds was getting the beds too nitrogen rich with compost and or soil mixes with added ferts. Everything takes off nice, looks pretty, but low production.

Then people try to correct it with more fertilizer, which maybe has less nitrogen like 5-10-10, but still too much in soil that's overloaded already, and you can't break that big plant/ low production cycle. Beds gets better that second year because nitrogen levels get more in line, they've been depleted the most by the wild foliage growth.

I've not tilled under new beds, this bentonite clay we have here, I'd doubt it would make much difference.

* As a disclaimer: My observations are often not grounded in science and are mainly intuitive in nature.

[ScottinAtlanta]

If your beds are 12 inches deep, there is no need to till deeper. Your plant roots will never go that deep. I have had great luck with mulched tree leaves - huge amounts of them on the beds in the fall. If you fill the bed to the top, by spring they will be 3 inches down and by the next fall, 8 inches down. Leaves are free, and full of micro-nutrients. If you mix layers of coffee grounds among the leaves, so much the better. Again, free for the taking.

[Ed of Somis]

Thanks for the input! An interesting idea about new beds having too much nitro. I wonder how prevalent that is. I am not a "science guy" either...experience can be a good replacement. As for the depth of tomato roots...I am quite certain my container plants have reached much further down than 12". Long ago I remember someone saying not to worry...the roots will break through the clay. I don't know.

[AlittleSalt]

I agree with Scott. Besides all the positive things in post #3 about dried leaves - leaves don't have seeds in them like a lot of other brown ingredients have.

[Labradors2]

I have raised beds on top of clay. We simply add aged cow manure each season, and it is now teeming with worms who can do the digging. The tomato plants can anchor their roots in the clay!

When I first started out, I would put aged manure or compost in each planting hole.

I've never had a problem of too much nitrogen. In fact, I was surprised when I submitted a soil sample for testing in the fall last year and everything was perfect - except that nitrogen was low. That year we had added one layer of aged manure the previous fall and another in the spring!

Linda

[Chapinz8]

I agree that 12" is all the depth you should need. I have 8" in some and 16" in others and I can't tell much difference. Most tomato roots for me tend to spread out more than down.

I would go easy on those alfalfa pellets. i got cute one year and mulched one bed with them. I've never been to the Amazon but that was the impression I got after a few weeks. Kind of interesting watching them break down however.

[Ed of Somis]

Well, I really appreciate all the feedback. I am encouraged that my clay native soil will not be a death sentence for my beds. I mean...in August the stuff is so hard (no summer rain here) you can see sparks fly off your pick when trying to dig through it. No lie. I guess I will just add tons of amendments/compost to my topsoil, and hope for the best. How do you age manure and when is it ready?

[Gardeneer]

On the soil depth, I think 12" is fine though more dept is better.
Tomato roots find the "path of least resistance" to expand. That is, if they cannot go deeper then can expand sideway/ diagonally.
My own raised beds are about 12" deep. But I have loosened up the bottom before filling and added some pine bark products. So if the roots are really interested, could go down more at their own risk.

[AlittleSalt]

Ed, The leaves help by separating the clay soil. Something else that helps is tilling in concrete sand. You can buy it from anywhere that sells sand and gravel. Silicon sand has extremely small particles, brick sand is more course, but concrete sand is closer to the size of aquarium gravel mixed with brick sand. BUT, it's next to useless as a nutrient additive. So that's why you might want to add all the stuff in this thread too.

Basically putting this: Clay soil particles are very tiny. Adding somewhat larger organic material breaks up the bond of clay soil - eventually turning clay soil into a friable soil that plants thrive in.

[Ed of Somis]

Thanks again for the ideas. Just to share a little knowledge (I have grown avocados for 40 years)...we add gypsum to clay soil around here. It is cheap and has the reputation of breaking clay up. Don't ask me how it works...but all the big boys around here do that.

[kurt]

Originally Posted by Ed of Somis

Thanks again for the ideas. Just to share a little knowledge (I have grown avocados for 40 years)...we add gypsum to clay soil around here. It is cheap and has the reputation of breaking clay up. Don't ask me how it works...but all the big boys around here do that.

http://eartheasy.com/raised-beds-soi...rements.html#b


In the meantime check out some of this info,it is not as bad as it seems.

http://www.finegardening.com/improving-clay-soils

Tomato transplants perform well in twelve inches or less in raised beds because the disturbed tap roots result in roots growing horizontally instead of vertically in the soil. Undisturbed tap roots can grow many feet deep vertically. I grow only in raised beds of 12" and 8" depths. Both perform well.

I use everything organic that has been mentioned. I don't use leaves unless I chop them with my lawn mower or leaf blower. The leaf blower works well when I attach the bag and vacuum the leafs. With hard clay soil, the organics and sand keep it soft. Alfalfa pellets attract and support earth worms which also soften the soil.

It always seems to work best for me if I work organics into my beds in early fall instead of late winter or early spring. The soil seems to perform best if allowed time and a few rains to get everything mixed well and the earth worms and bacteria working well. It also allows time for any excess nitrogen to wash out from the bottom of the beds.

Ted

[MissS]

Gypsum is a great amendment for clay soil, but to make it most effective add organic matter, otherwise it almost for naught. Gypsum opens clay soil and allows the organic matter to enter the bonding process.

Most clay soils are rather fertile even while they are dead-pan dry. Be careful adding fertilizers until you have had your soil tested.

Sadly, once that you improve your soil so that it is moisture retentive and drains well, nice and friable, then the nitrogen easily leaches out. But hey, the roots are able to travel further for food since the soil is so much softer.

[Ed of Somis]

I think you guys are absolutely right about the roots going horizontally if they encounter obstacles vertically. Today, when digging in the old section of bed...I noticed the horizontal travel of the old roots. It surprised me. For the last 3 years I have grown in large containers...and the roots go straight down in those.