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Watering
by Dan Clost
by Dan Clost

email: dan.clost@sympatico.ca

First serious garden earned 25 cents from the Kemptville Horticultural Society when I was 12. Have been poor in horticulture ever since but rich in spirit.

Went to work writing the Good Earth column (over 500 articles published in newspaper, magazine, website and journal.) and learned that what was printed wasn't what I wanted to say and certainly not what Gentle Reader understood me to say. Subsequently have developed a certain clarity and economy of words.

Day job- nursery and production manager for a large nursery/garden centre
Side job- Garden restoration and renovations, design consultations, remedial pruning.
Night job- garden writer and communicator (overnight success in another 20 years)

Dan gardens in Canadian Zone 5b


June 19, 2011

Watering is probably the one gardening activity in which most folks delight, perform most regularly and perform incorrectly most regularly.

Lawns, vegetable gardens, trees, flower beds, hanging baskets, containers and trees all have the same requirement- sufficient water to meet the needs of the plant.

We all know one inch per week is the amount needed to support a lawn. This is true as long as the cultural conditions are in place to support that maxim. The soil needs to be of the right consistency with the correct amount of organic matter and air space to hold the water long enough for roots to take it in. Compacted soil will not allow water to seep below the surface; sandy soils the water drains through too quickly; and, in heavy clay soils water doesn't drain at all.

Topdressing annually with a composted material is a very good way to address this issue. Let your grass grow a bit longer- say to three inches- as a water conservation strategy. The taller blades will provide more shade for the soil reducing evaporation. (This helps with weed reduction, too.) One of the best ways to have a good lawn with minimum intervention is to plant shade trees. If there is one group of trees that I would not recommend for this it is the Norway maple, Acer platanoides, which includes the ubiquitous Crimson King. (Other common cultivars in this group include Royal Red, Emerald Queen, Princeton Gold. Cromson Sentry and Harlequin- the white and green leafed one.) They have very shallow root systems that compete directly with the lawn. Trees that perform very well include the Honeylocusts, Gleditsia triacanthos, and Birches.

Water once a week, water deeply. Measure the amount applied. Start with the 1" benchmark and adjust depending upon your current conditions. Adjust those conditions over time to achieve that benchmark.

Shrub borders and trees have similar needs. An established long-term plant should be able to support itself with very little supplemental water. The essential condition is that there is room for the roots to grow. I should back up one step, it is also very important that the roots attached to the plant are sufficient to support the plant at the time of planting.

This is more important for larger plants such as trees. Although they are mostly container grown these days, field-grown trees, especially upright junipers and large trees, are very common in the industry. There are strict regulations concerning the size of containers, the length of time between harvesting and selling etc. designed to ensure that the plant is as healthy as possible when you purchase it. But compare the size of the root ball in a wire basketed tree to the root system of that same tree in its natural state. If you drive through rocky soil areas- granite tip of the shield up north or limestone plateau of the Champlain sea down south, you will see very large mature trees. Yet, if you tried to plant a large tree nearby, it would die. It all comes down to the ability of the roots to support the top half of the plant. My recommendation is to plant as small a tree as you can accept and let it adapt to its surroundings.

The next bit about watering goes back to the type of soil, sandy or clayey. The usual occurrence with the latter is that water pours into the planting hole. What I mean is that most folks excavate an appropriate size hole, plop in a plant and then fill the hole with nicely amended new soil. Water fills up the hole and then just sits there since the clay won't let it drain. The number one cause of planted spruce's demise in our area is drowning. Dig the hole, fill it with water and wait until it drains away. If it doesn't, plant some water-lilies and buy a goldfish.

Hanging baskets and containers are different. They are almost always chock-a-block with annuals and the trick is keep them alive until first frost. The plants dry out very quickly for three reasons. The first is obvious, the heat. The second is not so clear- the roots quickly fill up the container supplanting the soil which reduces the moisture holding capacity to zero. Purchase the hanging basket mix of plants that are attractive to you, and transplant them en masse to a more appropriate hanger, perhaps one with a fibrous liner, or one made with a porous material such as terra cotta. The third reason has to do with perceptions. We might have experienced a rainy week and are lulled into thinking all is well, forgetting that hanging baskets are often left dangling in an artificial rain shadow. Container mixes are important to use instead of regular soil (too heavy, settles in and compaction results.) Check for organic or non-organic moisture retention components. Some are good, some are scary.

Veggies need a slightly different regimen. I include, incorrectly but appropriately, in this category any plant that produces a non-seed portion which we intend to eat (beets are excluded.) For a tasty tuber, stem, leaf or fruit, we need lots of water. The plant's raison d'ĂȘtre is to reproduce. A lettuce plant doesn't care if we think it is bitter tasting; it just wants to bolt and produce seed. Hollow heart in a potato or blossom end rot in a tomato don't stop a plant from propagating itself but it does affect our enjoyment. So, water regularly- I have found that tomatoes especially enjoy being watered at the same time of day, and water more often-remember that what you will be eating will be close to 85% or more water.. Use the finger buried to the knuckle test to see if the soil is moist.

By the way, tomatoes are not fond of cold water. Collect rain water and use that.

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