Raised beds and water efficiency?

[GeorgiaGirl]

I'm reading a book called "Gardening When It Counts" by Steve Solomon. In it, the author talks about the trend of raised bed gardening and explains several reasons raised beds aren't best (except for certain specific types of vegetables).

One reason he gives is that they require more irrigation. He claims that during a period of hot, dry weather, raised beds will need watering whereas "slightly raised" rows will be okay in the same conditions without daily watering.

Instinctively, this makes sense to me... I haven't gardened in raised beds, but it seems that it would be similar to container gardening... containers, with their sides exposed to air and without roots that can tap deep into the subsoil, it's just an accepted fact that they need more watering (often daily) during a hot, dry spell.

Any thoughts on this? He also gives other advantages to gardening without raised beds (such as the ease of weeding quickly with a good sharp hoe, as opposed to having to pull every weed individually by hand). Since this is my first year to try to grow vegetables beyond what's in containers, I want to do it in a water-efficient way... but obviously I have to make this decision ASAP.

[Sage Hermit]

I ran into this issue as well but my solution to this is the same as say someone who is growing in a desert climate. I am setting up a water pump and hose to my raised beds and putting that on a timer, and mulching heavily. For me the reason I am going with raised beds is to control some of the pests and help fight plant pathology. Kind of like a large pot. and they look cool and thats all that matters to me... just kidding.

All a raised bed is is a bed that is above the ground level or has borders to it. They come in all shapes and sizes with some raised 3 feet while others are raised only 6 inches.
Thats my 25 cents...

I'm adding ... to seem cool...

[rainbowgardener]

Every gardener has to figure out what works for them. Where I am we have clay soil (moisture holding, doesn't drain) and lots of summer rains. Getting rid of the water is more important than hanging on to it! Raised beds are helpful.

But they aren't very much like containers being much larger, so stuff doesn't dry out like it does in little containers and isn't exposed the same way.

The advantage of the raised bed is you can fill it with exactly what soil mixture you want, so aren't dependent on what kind of soil currently exists. Much easier than trying to amend the existing soil enough. If your raised bed is full of very rich, composty, organic soil, even though it drains it will hold moisture, especially if you mulch over it once things are planted. So you really aren't losing too much.

He's right that you can't really hoe your raised beds. They aren't for people who are farming. No one who has 1000's of square feet under cultivation would put it all into raised beds with edging etc-- it would be silly and would multiply excessively the amount of work as well as being a huge investment of time and energy to build. Farmers do raise their rows by putting soil from the paths onto the growing row, without boxing it in. (the video of Emilia Hazelip linked in this thread https://www.helpfulgardener.com/forum/viewtopic.php?p=111580&highlight=ruth+stout#111580 shows pictures of what that looks like.) Raised beds boxes are for us back yard city gardeners with just a little bit of ground (or none -- I built two raised beds on my concrete patio so I could use it for growing). But in those circumstances, they do break down the gardening work into very manageable tasks.

[hendi_alex]

I don't think that a person can generalize about raised beds versus in the ground gardening as the individual results are probably very site specific. My site is very sandy and criss crossed with a huge number of competing tree roots. My raised beds are not in contact with the soil and are filled with a compost, manure, synthetic soil mix which holds a large amount of water. I generally have to water my in ground planting areas much more than my raised beds. I think that the construction of the beds can also be a factor. Where six inch raised beds may dry out very quickly, eight to fifteen inch beds would have a much higher water capacity with much soil being insulated from the heat and drying air. Since changing from 5-6 inch deep beds to 8-9 inch deep beds there seems to be a dramatic decrease in the watering needs of my raised beds. In late July through August, my raised beds may in fact need more water than the in ground spots, but Spring through late June it is no contest as the raised beds easily outperform.

[applestar]

That's really interesting Alex, since the usual advice is that higher beds need more water. It's a good example of exactly what you said re: site specificity.

[GeorgiaGirl]

GREAT points, everyone... thank you all, as always, for the great perspective!

[Ozark Lady]

I find that with using tunnels for shade, I do not have to water my raised beds daily.
If I do not protect the beds... the plants respire... and out comes the moisture.
I don't believe this really has much to do with the raised aspect of my beds. I lose moisture also if in the hot sun, with little or no shade.

I run into drought conditions in August, and oddly enough, by August... my spring raised bed, has broken down the nutrients, and is often a sunken bed.. below the grade of the surrounding land.

And still raised or sunken... my beds need shade from the hot sun, or lots of water to replace that which was lost.

Again, site specific, because others would have differing results.
My raised bed helps immensely in the spring rains... and yet, my sunken bed also helps immensely in protecting my plants from losing the water that I give it in August..

Except in years like 2009 when we had a very wet August.

[hendi_alex]

Over the years I've migrated more and more toward taking advantage of micro climates in the yard. My main gardening area, with the earliest results is in the full sun. It didn't take long to notice that some of the items, especially cole crops, lettuce, arugula, strawberry plants, etc. didn't do very well in that spot as the heat of summer arrives in mid to late June. My response has been to construct a series of raised beds on the east or south east side of some large oak trees. Those areas get full sun until between noon and 1 p.m. depending upon the exact position of the bed, and then diffused light afterward. Now the strawberries and raspberry plants live almost exclusively in that half day sun spot. Also, I am able to plant succession planting of many of the early crops, with early lettuce going in the sunny garden but later lettuce going in the half day sun location. This adjustment has allowed us to plant succession plantings of many crops and keep them producing much longer than is possible when just using the full sun gardening area. BTW, the half day sun locations only need a minimal amount of watering, even in the heat of the summer.

[Susan W]

FWIW, I'll add some stuff on raised beds. Over time have put in several in the back yard, 4' x8' (easy dimensions when buying the timbers!) I am working on long beds combining the end-to-ends. Having 2' in between was work to keep clean, mowed etc. Most of what I have are flowers and herbs, about all perennial.
As I am re-working them, am digging out, throwing out rotted timbers, adding a plastic barrier, pounding down to ground level (4' sections from box store), putting new fresh timbers on. I try to refresh the beds at least once a year.(not the whole new timber process!) That being waiting for new growth to show, cleaning, adding top soil and humus. With our rains, the beds sink some, so reason for extra stuff put on, freshening the beds. Then I go back and mulch, try for 1" shredded hardwood. The extra plastic barrier is helping to keep out grass and other weedy things.

I will mention that I do up close and personal gardening. Get down with hand cultivator and just work the soil. With the beds only 4' deep can reach from either side. I carry my plastic tote with hand tools, phone, cold beverage of choice, pad to kneel on and go chill!

As for watering? Do very little. I usually hit the containers, hanging baskets and of course bird baths daily, and spot check the gardens. May do a spot water of a couple things, especially if new or looking droopy.

We even have a bit of snow on the ground, so at least fun to talk about this!

[Cagolddigger]

Great subject.

I've had the benefit of seeing first hand the differences between just planting seeds in furrows and raised beds in my garden. I have noticed that much depends on the soil and (as stated above) the micro climates in the garden.

I first started with your basic furrow planting my first year. The soil was not amended in any way and I always felt I was needing to water. The ground would crust easily and weeding was a pain in the edited.

I did some research and decided to try out raised beds. I don't have money to spend on lumber to enclose my beds, so I just piled up the dirt and made beds. I didn't have compost yet and just planted willy nilly. Again, the ground crusted, the watering never ended, and the weeds .

The following year after having done more research and having a nice pile of compost, I amended my beds and took careful consideration when planting. I put the most heat tolerant plants in full sun and the others specific areas that would benefit them the most. I also use a plant to help shade others. I inter planted with beneficial plants for pest control. I soon realized that I needed to water less, the ground stayed nice and fluffy and beds that had less ground exposed stayed moist.

Always keep a journal. Write down everything. You won't believe how much it helps.

[a0c8c]

I had to water my plants in the ground daily anyways, so watering daily in a raised bed wouldn't bother me. My container plants didn't dry out much faster, since the extremely parched earth wicked away water in all my gardens verey quickly.

[rainbowgardener]

Yes, one of the things my year on this forum has taught me is the importance of understanding the local conditions. I came here thinking I had many years of experience in gardening, but soon realized that I have many years experience in gardening IN CINCINNATI, OHIO!! Some basics are translatable to other places, but always "mutatis mutandi" -- all necessary changes being made, the translation being done.

Gardening in TX is very different than gardening here in Ohio, where water just falls out of the sky on a regular basis through the growing season, is different from gardening in parts of California where it never freezes, etc etc

Each of us has to figure out by experimentation and observation, what works for us with our climate, soil, micro-climates, etc. The journaling is a very good suggestion!

[Ozark Lady]

Use your camera too.
I got into the habit of at least weekly photos, these are digital and when I upload them, I get dates.
I can look through my photos to see when things were done... Not the exact date, but what week.
I find this really helps me. A photo just captures so much more than my notes do. And I seem to keep up with the photos better than my notes written quickly in the garden!
End of season, I go through and make small albums... for comparison with the coming season. I can spot trends... how fast that tree or bush is growing etc... Lots of things that I miss in writing notes.

[thanrose]

I have two friends that live in the same Florida city, and both have grown large vegetable gardens for decades. One tells everyone to do the opposite of raised beds: ditch everything, year round. Our poor sandy soil just dries too quickly, so if you plant everything in trenches they stay more hydrated with cooler roots. The other plants everything on mounds, even potatoes. The water table is too high, he says, we need to keep the plants from drowning. He'll mulch the potatoes with hay or with pine straw, which fills all his trenches between the rows anyway.

And they are both right for their particular conditions. Now, me, I've got marl (clay) in the front yard and sand in the back.

Down here I have to keep any containers on the large to very large size and lighter in color, because the roots will bake in the pots if I don't. Large raised beds would serve me well in both yards.

[wolfie]

I think it also makes a difference of how much actual dirt you have revealed. I do the companion way of gardening, and I plant very close together, keeping very little open space of dirt once everything gets going. My pepper plants all touch creating a covering, which I think keeps the sun from drying out. I also do the raised beds, 8'x4' and about 12inches deep once I get em mulched with compost.

[Ozark Lady]

I agree with the amount of dirt revealed.

I use a heavy mulch, until the plants themselves create a micro-climate and humidity zone.

Yesterday, I worked on two beds, no not digging, it is wet and frozen..
But, I piled a huge pile of leaves on one, and covered it with a plastic tunnel. In the other I removed all mulch and erected a plastic tunnel. In a third and fourth bed, I simply removed all mulch.

Why? I want the leaves to compost down, a bit, not all the way on the one bed, so I am using the tunnel to focus some heat.
That will soon become my potato bed. The second one in the tunnel... I am starting seeds for... cabbage, broccoli, cauliflower, brussels, and I want that soil warmer for receiving the seedlings when they are ready for transplanting. And the other two, without tunnels... one is for onion sets, lettuce, radishes etc... I need it to dry out and warm enough to be able to plant these... I can't dig in frozen soil. And the other one is for green peas.. Yep my two problem children... green peas and onion are getting another attempt this year... as is brussels.

If none of the three co-operate... it is fall crop attempt or winter growing for them!

But, did you notice... I need to remove the mulch to let them dry out some... they are too wet to dig.
My beds are also 4'x8' that is the easiest size to make with the available garden timbers. Those treated timbers, are holding up well, and they have been there for 5-6 years. Sure, corners come loose and must be repaired, but that is the nail, or screw rusted out... not the timber.