Tuesday, April 26, 2011

Watering the garden in Central Florida

A commenter asks about watering. There's a very long answer that I have been articulating in my head for a while that involves various ethical and economical tradeoffs. But the short  answer is easy: You need to water as much as the plants need, and more specifically, you probably need to water a lot more than you currently water. Certainly that has been the case for me: Slowly over the past five years I've realized a simple and obvious truth: Plants need copious water to grow well here, with our (sometimes) arid climate, strong sun, winds, and overly-drained soils. It is, in fact, very difficult to over-water here in Florida (barring the mucky soils we have in certain regions in Central Florida). Water is often the limiting factor in a home garden and dooryard orchards. Most people simply don't water enough, and water-deprived plants are unhealthy plants.

Reading gardening books for northerners, you often read about watering "deeply" rather than often. By watering deeply (so goes the thinking), you take advantage of the holding capacity of the soil, and plants can "help themselves" to the residual water in the soil.

Doesn't work here in Florida. Really, no matter how much organic material you rake in, no matter how thick your mulch, you're going to need to water often, and therefore, don't bother watering deeply. That "deep" watering is wasteful: Most of it drains out of our soils. (If you ever look through a microscope at sandy soil, comparing it with more typical, loamy/clayey soils like the kinds we find in the Midwest, the grains of sand look like boulders next to the tiny particles from "real" garden soil. What makes clayey soil clayey is precisely the particle size. The space among those sand boulders acts like a sieve, flushing water from the soil. When we take the kids up north, they are fascinated by puddles because here in Florida, we just don't have many.)

Especially during our peak growing months in spring (March and April), when rainfall is relatively rare, the air is clear, the moisture-robbing winds are brisk, and the sun is strong, you need to water daily, until the root zone is well saturated. Most days, I stick my finger in the ground when I come home around 6. I expect the soil to be dark and moist.

It takes a lot of water to do that during our hot-dry spells.

I use a mix of microsprinklers and conventional sprinklers. The latter are jerry-rigged: I mount Orbit flush-head sprinkler heads onto six-foot PVC risers in the center of my garden: I get very even, quick coverage over a large-diameter circle. I water my main garden bed about 15 minutes every day, mid-morning. My remaining areas are irrigated using Mister Mister system, which lets me water very precise areas, very precisely. I run lines into my pots and use 360° sprinklers under fruit trees, and then position 90° sprinkler heads so beds get watered "from behind"... There are many arid areas in my garden beds where I plant drought-tolerant plants, but they tend to be in the backs and corners of beds.

Look, water in Florida is cheap (too cheap). One day soon, we'll face some serious capacity issues, but not because of my vegetable garden. Blame the resorts with ten acres of St Augustine, exposed to full sun, and the jackasses with an acre of turf in their private residence who run the sprinklers every morning during the rainy season. (I have one of those neighbors behind me.)

If you garden, balancing real ecological concerns and the natural desire for plentiful blooms, fruit and vegetable is tough, but the alternative to watering sufficiently is (obviously) underwatering, which is itself wasteful, as that insufficient water is itself still a consumed resource, but one without the maximum yield (however you figure it). If you plant a rose bush or a squash plant, you basically commit to watering it enough. Otherwise, don't bother planting it in the first place. 

11 comments:

Amber said...

Well said! This time of year is the worst for watering.

templeterracegarden said...

Love this! I have been struggling with this very debate as it's my first year veggie gardening. And when all is said and done, I'm just far too sympathetic to leave my plants to wilt in the ground. If I have to lug water in buckets by hand to get around the watering restrictions, I will, rather than see my plants suffer. (Though in fact I'm getting good at setting the sprinklers just high enough to cover the green bean bed, but not high enough to be visible on the other side of the privacy fence).

I never water grass in Florida. And I'll never plant St. Augustine again. I never run the sprinklers mid day, when it's crazy hot and all the water just evaporates. But I water as often as the plants need it.

I am planning to invest in some rain barrels soon - both for the environment and my wallet!

Farmer Dave said...

This is excellent. Watering has always been my nemesis here as well.

May I link to your article from my site?

Florida Hydroponics said...

Good Posting :)
Watering here in Central Florida is very tricky and the weather is VERY unpredictable.
I set up a hydroponic system last summer and that was a little challenging (with the sun drying up the rockwool slabs VERY fast) and it needed water at all times of the day (when it was very hot - 110+ degrees most of the time)
This year I dug up a spot in the yard next to my greenhouse and added a soil garden. I'm almost 100% complete with the irrigation (micro drip), but that was a chore in itself. But so far... all works/looks good and seem to be getting a good amount of water daily.
I'm doing some spring cleaning to the greenhouse now, so hopefully I will have another hydroponic system going in there soon =) This time I might use a coco fiber mix, so it holds moisture better than rockwool and doesnt dry out as fast.
I wish you and your garden much success this year =)

aborbon said...

I've read about watering deeply and noticed that the water does just pour out of the bottom of my raised bed. My bed is 1/3 yard sand, 1/3 fancy stuff from A Place in the Son off of Kepler (Yay DeLand!) and 1/3 top soil from Lowe's. I did this to save money but I also find that I have to water more frequently than deeply. Thanks for the informative post!

Michael said...

dave, feel free to do the linky thing. abordon--you should try volusia shed. i love a 50-50 mix of their topsoil B (lots of peat) and mushroom compost. i've also gotten into sunken beds, which are a real pain in the rump to "build" but are a dream to keep watered...

Farmer Dave said...

Thanks, Michael.

I've been moving towards sunken beds myself - did that this year with the cucumbers (put 'em in shallow holes rather than on hills) and they're doing better than previously. I haven't found much info on the method, however - most people are using raised bed ideas that seem more suitable to less sandy soils.

Lovingmama said...

Thanks! I am from up North and completely understand what you are saying. This will be my 3rd garden in FL and I feel like I learn more and more each year. I am using a combination of watering and will see if stepping it up a bit helps my plants look better mid-day.

Melissa said...

Thanks for this! I'm a relatively new gardener in Central FL - trying so hard to grow veggies. I've worked so hard this spring to plant my biggest garden and it's just not as productive as I'd like. I'll keep reading your blog.

Anonymous said...

I've had the best gardening spring in my 20 years of living in central FL. I owe it two two things. H2O and mushroom compost. I mixed lots of 1 month old aged compost into the garden. I lay soaker hoses on the surface along the center of the row. I then planted my tomatoes, peppers, eggplant, lettuce etc.along the hose. Then I mulched heavily (3-4") with fresh mushroom compost. I then let the hose stay on at a slowwww trickle. If it rains I'll turn it off. I have had no weeds! The plants never wilt, and are the happiest plants ever. No disease, few bugs, lots of veggies. It has saved a lot of water, and I think the lack of water except right at the wanted plants has kept the weed seeds dormant. Hope this works for others! Happy gardening.

Anonymous said...

Here in the Tampa Bay area, I water every day after I get home from work, and on Sundays I mix some plant food into 2 gallons of water in a watering can and feed the plants. So far, so good. All plant look healthy, growing well, and some have vegetables starting to form on them.

I have most of my plants in rubbermaid boxes, or dug into a hole in the ground. I mix 3 parts garden soil, and 1 part sandy soil that I dug up. I also take the old dead leaves from my oak tree and put them in the bottom of the bins or holes before I pour in the dirt.