Sandy Soil

So we just moved to this land from the city. Yay! I've read Gaia's Garden and Steve Solomon's Gardening When It Counts, which recommend very different ideas for veggies. I was thinking of doing sheet mulching in raised beds now and letting them sit until spring (per Gaia), but Solomon has convinced me that I should dig the soil and just do it in the ground using his Complete Organic Fertilizer. I am conflicted about which method to follow. Advice? Also, why do all the books constantly talk about clay soil? No one mentions sandy soil. I live on California's central coast and have very sandy soil. I tested my soil with a quart jar according to Solomon's advice. Here's the picture:

"0" is the initial soil level, "2m" is after two minutes and "2h" is after two hours. Also, I did a percolation test. It said percolation at over 4" per hour was bad. Ha! I did 5" in 15 min. So Solomon says sandy soil needs frequent light waterings so the soil nutrients aren't leached away, but I've also read that sandy soil needs infrequent, deep waterings, so the roots grow deeper. Ugh! Why is this so difficult?? I need help, people. What should I do? What method should I follow? Should I read another book? Thanks for your time and advice!

You don't need to be doing "frequent, light waterings". As close as you are to the coast, you don't have a problem with too much evapotranspiration; I'll bet you get fog every night, right? What you do need to do, during the dry season, is to water infrequently and let it soak in deep. But now that we are in the rainy season, your number one project should be to get some more organic material worked into the soil, and that will help to hold more soil moisture. Can you get down to the beach and load up some buckets and barrels of seaweed? That's excellent organic material to work into the soil, and a storehouse of minerals as well. The other thing that would help would be to work in some biochar. Take a look at some of the other threads here on Permies about how to make and apply biochar.

And why wait until spring? This is a great time of year to plant some broccoli or other cabbage type veggies.

John, thank you so much! That really makes sense about the evapotranspiration. We do get fog every night. On a hot day it burns off early, but often stay until 11am or later. I had just been thinking about the seaweed when someone complained about how expensive kelpmeal is. I thought, "Hey, I can get kelp for free!" Should I dry it out or bury it or what? I'll look into the biochar as well! However, I have a gopher problem to deal with before I start our garden, and I want to get our fruit trees in first, so for now I am shooting for the vegetable garden in spring. Thanks for your advice! It was really helpful!

When collecting kelp for the garden, you just need to give it a good rinse -- don't want to be bringing any sea salt into the garden. Once it's rinsed, just dig it in good.

As for the gophers, they aren't all that bad according to this video:



I have a live and let live arrangement with the gophers in my garden. They get to gnaw on a few old, woody carrots in exchange for keeping my Georgia clay from getting too compacted. If you are losing too many carrots in your garden, I suppose a cat would help cut down on their numbers.

Here's what I'd do if I started again on my ex-beach (literally):
Not do raised beds. I read a load of stuff that was clearly aimed at climates waaay colder, and soils waaay clayier than mine.
I built raised beds. They were a total nightmare as the gagillion gigaliters of sand under them just sucked the water down,
coupled with the extra exposure to drying winds and sun.
The ones I could be bothered, I dug out the amended soil and wheelbarrowed loads of the basically pure sand underneath onto paths.
I dumped heaps and heaps of seaweed, manure, grass clippings and compost in,
heaved the amended soil back on top, gave it a bit of a fork over, watered it really heavily
and threw as much mulch as I could on top.
If I'd known about buried wood at the time, I would have done a modified hugelkultur and put a ton of wood in the bottom before adding all the other stuff.
I'd give it a week or so to settle, but brassicas, fava beans, chard, daikon and other winter veges would handle the chaotic soil situation.

John Elliott wrote:When collecting kelp for the garden, you just need to give it a good rinse -- don't want to be bringing any sea salt into the garden. Once it's rinsed, just dig it in good.

I don't even rinse my seaweed-apparently the harmful sodium chloride (table salt) is a very small proportion of the beneficial mineral salts in seawater,
and in sand it vanishes even more quickly than good things like organic matter!
Damn sand
Over here, quite a few 'biological farmers' even spray dilute sea water on their pastures...

Joy Stefoni Fisher wrote: Solomon says sandy soil needs frequent light waterings so the soil nutrients aren't leached away, but I've also read that sandy soil needs infrequent, deep waterings, so the roots grow deeper.

From my experience, nutrients will leach in sand at an alarming rate however you water, and shallow, frequent watering will lead to shallow, drought-susceptible roots.

That guy in the video must have much nicer gophers than those I have dealt with.
The ones who plagued me would drag about two feet of the plants into their tunnels, and munch away.
They would kill a new plant each night.

I never developed that same "Live and let live." attitude for the destructive bastards.
I toiled all spring just so they could have a few weeks of fresh veggies, with none for me.

Sandy soil can gain huge benefits from the addition of clay. The best way to incorporate clay is by putting plenty in the compost pile. This helps to trap compost nutrients and to create humus. Without clay, organic material in compost is more likely to gasify and allow formerly locked up nutrients to leach away once they are no longer attached to something. Sometimes it appears that soil has been added to a bed, but it is quite unstable and fleeting due to the tendency to gas off. It works as a mulch, but doesn't add much in the long run.

If clay is unavailable, fine silt is an option. It won't hold much water on it's own but will incorporate with rotting vegetation and form a more stable soil than one of just sand and compost.

Biochar would be a welcome addition to the soil since you get moisture retention, a nutrient sink and a home for millions of micro organisms. It could be added directly and through rich compost where it will absorb nutrients that are prone to leaching.

A combination of all of this will transform your soil in a way that compost and rich organic amendments alone never could. It's a very simple matter to add needed amendments. If you're to reap long term benefits, the water and nutrient holding capacity must be permanently changed.

This seems like the perfect spot to include a clay bottomed hugelkultur pit. It could come slightly above grade, but will dry out if built very tall.

If you want garden beds for zone 1 gardens, you would do best to do growbox or Aussie-style wicking beds. Big cattle tanks with solid bottoms to hold in water and keep OUT gophers.

I have a situation with low organic material in sandy soil too. We live away from the sea, so I'm collecting a ridiculous amount of fallen leaves and I'll place it directly on the garden, wet it down, and cover for the winter with a tarp. The soil organisms will go to work on that for me...

Leila Rich wrote:

I don't even rinse my seaweed-apparently the harmful sodium chloride (table salt) is a very small proportion of the beneficial mineral salts in seawater,
and in sand it vanishes even more quickly than good things like organic matter!

For what it's worth this is also the opinion of W.A Stephenson author of "Seaweed in Agriculture an Horticulture" which for years was more or less the definitive volume on the subject (and may still be for all I know.

I throw seaweed I pick up into my compost.

edited for spelling

So you have sandy soil, other than adding bio-char there is not alot that you can do.

1) Have 40% of your garden as nitrogen-fixers, legume/silverberry family.
2) Your veggie growing season has to be the fall/winter/spring the opposite of other ppl.
3) Plant traditional desert plants like the mint family, sea kale, almonds, apricots, figs, dates/palm, etc
4) Mulch your garden to save water
5) Instead of growing in raised beds, grown in sunken beds
6) Use groundcover vines as your living mulch. that can be watered from a "centralized location" and can grow out 100ft in every direction

This is all so helpful! Thank you! Lots of food for thought.

Does anyone have book recommendations for my sandy, dry situation? I was planning on doing hugelkultur because we have a ton of wood laying around, so I will do it below ground and look into the clay bottom.

I had another question about a soil test I did. My husband dug a post hole so we could see the layers of soil and about 30" down it was so hard, he couldn't go any farther. I think it may be sandstone. Apparently our house is built on solid sandstone. When we were digging a trench near our house, we had to use a jackhammer for part of it because it was solid rock. Is that going to be good because it may hold the rain or bad because it will just run away. What does that mean for roots? We do have trees (live oak, cedar, acacia) around our house, but not in the area where we dug the post hole. Any ideas/advice?

R Scott wrote:If you want garden beds for zone 1 gardens, you would do best to do growbox or Aussie-style wicking beds. Big cattle tanks with solid bottoms to hold in water and keep OUT gophers.

Wicking beds! WOW!

First, I'm a Soil Scientist with USDA. Secondly, I am in a somewhat similar situation in that I live on very sandy soils and am also an avid vegetable gardener. Some recomendations to consider are, just how deep is the "sand" on your land before you hit more loamy or clayey soil? In my instance, I have bored down as deep as 10 feet and hit nothing but sand. I finally hit a water table around 10 to 11 feet. Why is this important? The loamy and clayey layers will restrict and conserve the downward flow of water. If these layers occur within a foot or so of the surface, you are in good shape because roots will be able to extract moisture and nutrients from these depths. If, however, your soil is like mine, with no loamy or clayey layers anywhere in sight, the measures I am about to discuss become even more critical. Secondly, I would suggest you have a soil test run. Many states offer testing for lawns, gardens, and cropland through their county Ag Extension Service.

Now, for the things you can do yourself. Sandy soil most certainly DOES leach many nutrients. First and formost of concern is lime. (assuming your soil is acidic) Lime helps regulate pH. Having a pH somewhere in the vacinity of 6 is usually desirable. Many nutrients are unavailable to plants without the proper pH level. I generally recommend applications of dolomitic limestone AT LEAST every other year on sandy soils. Lime can be added anytime and will not harm plants. However, it takes 5-6 months for the lime to break down enough to begin to work, so the sooner the better. The soil test I mentioned should give you a recommendation as to the amount needed. Personally, if I knew my soil is acidic, I'd go ahead and apply some now.

Your next concern should be to incorporate organic matter. Sandy soils are usually conspiciously devoid of OM. OM will do several good things. First, it will increase the water holding capacity of your soil. Secondly, it will increase the Cation Excahnge Capacity whick exxentually is a fancy way of saying it will hold larger amounts of nutrients that are available to plants, instead of allowing them to leach downward. Finally, it will improve soil tilth. I use a lot of tree leaves. I rake them up in the fall, and run them through a mulcher right into my garden space. I do NOT recommend using grass clipping. They often contain weed seed that will infest your garden. Same goes for some manures. Chicken litter from poultry houses is usually ok, but there is some worry about heavy metal toxicity from the feed they eat. Do this in the fall or winter and get it incorporated through tillage before spring.

When planting time comes, do not use ridged up rows. The main purpose to ridging rows is to allow soil to dry out and warm up quicker than the surrounding soil so the seed can get a head start. On sandy soils, this is not necessary and actually detramental. Sandy soils stay TOO dry. The ridges only function to shed water to the surrounding soil, and sometimes don't allow the seed to get enough moisture to germinate and grow. They will also prevent the plants from getting the most out of your irrigatgion water. Therefore, the solution is to plant a "flat" garden.

As for irrigaton, in your case, it appears you are in an arid area of the country. Evapotransporation is of big concern there. I use a sprinkler system here, but I am located in the humid southeast. In your situation, I'd suggest a soaker hose, or drip emitter irrigation to lessen the amout of water you lose to the atmosphere. I'd water long enough that the soil is moist 3 to 4 inches deep. I usually water my garden every other day (unless it rains) during the hotest part of the summer. If possible and practical, mulching on top around your plants with organic material will also help conserve and hold in moisture.

I hope this helps. Good luck!

I just read where you did the post hole diggers to see what you have deeper down. 30 inches is really not so bad. You still have plenty to work with. The sandstone may slow water movement down slightly, but it is usually porous enough and has enough cracks that water has little problem getting through it. If you want to know more about the soils where you live, what kind they are, try: http://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm

Thank you so much, B Ward! That was very clear (for a beginner like me) and helpful! Your recommendations sound similar to what I've read in Steve Solomon's Gardening When It Counts. Do you know/like him? Any book recommendations?

@ Joy

I've lived with sandy soil much of my gardening life. The advice you're getting here is great. I've found that double-digging works quite well, even in my sandy soil, and it's a lot easier than sheet mulching.

http://www.floridasurvivalgardening.com/2012/10/october-natural-awakenings-article.html

However, I do dump lots and lots of organic matter around long-term perennials. I have a tropical food forest in progress further south and the soil transformation there surprised even me (and I thought I knew what I was doing):

http://www.floridasurvivalgardening.com/search?q=south+florida+food+forest


"Sandy soil can gain huge benefits from the addition of clay. The best way to incorporate clay is by putting plenty in the compost pile. This helps to trap compost nutrients and to create humus. Without clay, organic material in compost is more likely to gasify and allow formerly locked up nutrients to leach away once they are no longer attached to something. Sometimes it appears that soil has been added to a bed, but it is quite unstable and fleeting due to the tendency to gas off. It works as a mulch, but doesn't add much in the long run. "

Yes - true. If you can find clay. That's something I need to get. I went hiking in the Appalachians a month or two back and should've grabbed a few five-gallon buckets of that rich red stuff when I was there...

To answer one of your original questions, "Why does everyone talk about clay soil". I think because generally clay soil is considered more of a challenge (I could be wrong) to "fix" than sandy soils.

As for me, I have sand for as deep as one can see here. I am breaking all the rules with my 8" tall raised beds I guess. I've fill them with a lot of organic matter and keep them mulched. By no means is my garden setting the world on fire but I am happy with where its going. I think the soil mix you have in the raised beds needs to be designed for maximum moisture holding.

Anyway, have fun with it

"Sandy soil can gain huge benefits from the addition of clay. The best way to incorporate clay is by putting plenty in the compost pile"

Our biggest garden is very sandy (reclaimed desert); down to 1 or 2 feet it's like sandy soil, but after about a foot or two, it's like clean beach sand down at least 6 feet. But there is a nice hillside of dry powdery silt nearby (so fine that for years we considered it clay, and use it for making figurines and models). So when we don't have sawdust or autumn leaves for the compost toilets, we bring a truckload of this dry powdered silt. I suppose it will take years to really change the soil, but it's better than the normal practice here of just bringing dry garden soil to the composting toilets.

So I understand that I shouldn't do raised beds because they will increase the loss of moisture, but I have a crazy gopher problem. I had been considering wire beneath raised beds for the annuals, putting my trees in wire baskets and even putting wire below hugelkultur. We've also played around with the idea of digging a trench around our annual beds and filling it with concrete. Lots of initial work, but maybe it'd be worth it long term. What do you think?

David, thanks for the links!

Brad, I am happy to hear the raised beds are working for you! Maybe they would work for me too...

Thanks for your input, Rebecca!

Add more plants. This sounds wierd, but the more you need organic material the more you should plant. The plants may not be very yummy the first generation, but as you continue to chop and drop you will build up your soil. The more you plant the more variety you add the better the soil becomes. Plants are the great accumulators of nutrients. The great catalysts. plants are the magic. Have a great day.

Joy,

Read the Intelligent Gardener by Steve Solomon and Erica who lives in your town.
Erica could probably help you more than anybody else. She knows your problems.

Dave Rogers

I have the same problem with sandy soil but my ph is to high. What would be the best solution