Lukelukeluke
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Irrigation in warm climates

Hello,

I am looking for some advice about irrigation in warm climates.

I've been working on a project in Northern Portugal (www.flirtingwithyurting.com) since January. We have already started growing quite a lot of fruit and veg and, considering what we started with, it hasn't been too bad. The main problem we are facing is how to most efficiently water the annual veg. The fruit trees and perennials seem to establish very quickly and are quite happy being left to it with a big pile of mulch around them. We have found however that the annuals are much more thirsty (probably because of smaller/less developed root system).

We mulched all the annual beds with newspaper and then shredded bracken/leaves or whatever else we could rake up. In the UK, I've found this method to be sufficient enough to stop watering all together with most crops, once they are settled in. But Portugal is obviously much hotter, and receives less rain in the summer. Furthermore, the soil here is very sandy so it doesn't hold on to moisture for long. We are having to water the annuals quite frequently, but the mulch prevents the moisture getting into the soil, so we are throwing much more water onto it than if we had no mulch. It is currently quite inefficient. The locals use flood irrigation. They make gullies between the rows of veg and flood the whole veg bed once or twice a week (water is not in short supply here as nearly everyone has a water mine/spring). This seems like a great idea were it not for the massive soil erosion and over time it increases salt in the soil. We have also considered leaky pipe, but I've used them before and I HATE them. They cost money, they restrict access to the soil, generally get in the way and end up in a mess.

So.... Has anyone got any tips on how we can keep are annual veg well watered?

Thanks very much

Luke

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rainbowgardener
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It's not an overnight solution, but one thing you want to be working on is amending your soil so that it is not so sandy. Keep adding compost and organic matter to your soil so that it gets more loamy. It will hold water better.

You are right that "throwing" water on top of your mulch is very inefficient. What you really want to be watering is your roots and soil. For large gardens that basically means some kind of drip irrigation system. Look up some of the posts by TheWaterbug. He is in hot, dry LosAngeles, Calif, USA and seems very knowledgeable about drip irrigation. For smaller gardens or if you have a lot of people sharing the work, you can just hand water with hoses or even watering cans (I water my small garden, carrying water in watering cans from my rain barrels), being sure to put the water directly in the soil near the plants.

Welcome to the Forum!! I looked at your website. It's an amazing project and a beautiful place.

Lukelukeluke
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Yes you are right about the soil. We have accumulated vast compost piles from all the land we've been clearing since we got here, + have lots of poo from the rabbits and chickens to put on in the autumn, and only this week we found a good source of free horse muck. The lands been left for 40 years so it's going to take a while to get the soil up to scratch.

DoubleDogFarm
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Luke,

Tell use more about the terrian. Flat, sloped.

Have you thought about berms and swales on contour or hugelkulture?


Eric

Lukelukeluke
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Hi Eric,

We are on a south west side of a valley so get really good sun. The land is all terraced with a gradual, very gentle slope (perhaps 1 meter drop for every 100 meters in length).

We have a friend who has built a swale and is experimenting with hugelkulture. To be honest, a swale isn't really going to be appropriate with the location of our annual beds, and the scale on which we are working. Lots have people have suggested using wood however, so I think we are going to stop using newspaper, and use woodchip/bark as mulch which can be dug into the soil when we replant the annuals. That should help let more moisture into the soil and keep it there for longer.

imafan26
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Adding organic matter in the long run will help the soil retain water. Compost, wood chips are also good materials.
What vegetables are you growing? There are some vegetables that can be grown that will use less water. Kale, couve tronchuda (Portuguese kale for caldo verde), peppers, squash, tomatoes, chard and other vegetables with green gray leaves and deeper root systems might do better.

If you are on a terraced garden, furrow watering is probably the most efficient way to water especially if you don't use soaker tubing.

It could be possible to do a hybrid watering system at least for some of the plants. You would need gallon milk jugs, or 2 liter watering bottles. The comments to this link said to put sand in the bottom of the bottle to slow the flow of water out of the bottle. It does not say this, but if you are not using a timer and connecting the hose to a faucet, and running it manually, you should place an anti siphon valve on the faucet to protect the water supply from contamination.

https://www.providentliving.org.nz/garde ... rrigation/

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SatyrGrey
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On top of the soil amendment, which will help your soil retain moisture, you need to do two things...

#1] DROP YOUR WORK SURFACE--- In arid climates, you want to create a crater around your plants; sunken garden beds, etc. to allow water to pool around them, and stay there --- (You want to give a tree a moat so it isn't sitting in the middle of a puddle, allow it to have an island so you don't drown the roots)

#2] MULCH-- Arid climates means the surface will dry too quickly if it's not covered, throw down some gravel, or better still, wood mulch. This will help prevent evaporation, and will also help regulate the temp of the soil.

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rainbowgardener
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SG - Just a little friendly advice to help a new member get started on the right foot. You seem knowledgeable and with good ideas. If you are going to come late to old posts sitting around (which is fine), it helps to be sure you read them carefully. Lowering the work surface is a really good suggestion. Adding mulch is pretty redundant, since Luke had said that their mulch was part of the problem in making it harder to get water to the soil. He said "We mulched all the annual beds with newspaper and then shredded bracken/leaves or whatever else we could rake up" and then later in response to comments he said "Lots have people have suggested using wood however, so I think we are going to stop using newspaper, and use woodchip/bark as mulch which can be dug into the soil when we replant the annuals" Since he's saying they mulch a lot and that is causing some of their problems, it looks like you are not paying attention when you come along a year later and say, hey you should be mulching.

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SatyrGrey
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Yeah, I guess I missed a bunch, it was pretty late when I posted--- Usually I am better about that! :oops:

DoubleDogFarm
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Oh, Don't worry about it. It's slow around here and members get a little edgy.

Start a new topic. :)


Eric

imafan26
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Location: Hawaii, zone 12a 587 ft elev.

You can practice some of the dry gardening techniques which advocates using a lot of mulch to retain water but to also select cultivars that are suitable for your climate, watering deeply, and space plants farther apart.

Some of the more drought and heat resistant plants would be NZ. hot weather spinach, vegetable amaranth, Asparagus beans, bitter melon, cherry tomatoes, hot peppers, and just about anything that would grow wild.
Plant early maturing cultivars and do most of your planting to take advantage of the rain you do get.

I find that if you don't pamper your plants, they get used to the conditions they are growing in and send deep roots down to get the moister deeper in the soil and they can tolerate longer periods between drinks.
Don't expect huge yields if you expect them to survive on rain alone. During the driest periods it is still best to deep water enough to maintain growth.

When you do water, make sure you water deeply, if you have added a lot of organic matter to the soil it will help hold moisture and so will mulch. Drip irrigation at the soil level and under the mulch loses less water to evaporation than overhead watering which takes a lot of water just to get the mulch wet.

https://www.harvesttotable.com/2009/02/dry_gardening/



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