TIps for Watering Your Plants

For those of us with growing boxes on the roof, we are deep into growing season. You may not have access to the irrigation system, or you may only have partial access. We do have rainbarrels (2 per building) to help to water your plants.

Herb Garden

Tips For Watering Your Plants:

1.      Check Moisture Level – Before watering plants, check to see if your plant really needs it – the top of the soil can look dry, even though just below the soil line it is still moist.  Stick your finger into the soil all the way to the second knuckle.  If it feels dry at your fingertip, your plants need water.  Too much water can be just as damaging to plants as too little.  If your plants’ foliage begins to brown at the edges and fall from the plant, you may be overwatering.

2.      Water the Soil, NOT the Leaves – Don’t wet the leaves when watering plants.  Always water at the plant’s base.  Some plants – ones with hairy leaves – are susceptible to sunburn if you get water on their leaves in the sun.  Water droplets can act like mini-magnifying glasses and burn your plant.  Even if your plant’s leaves are smooth, it is still a good idea to water the soil and not the leaves, if you can.  Remember that it’s the roots that need the water, not the leaves.  Wet leaves can lead to an increased chance of fungus, mildew and other diseases.  Apply water to the base of the plants where it can soak down to the roots.

3.      Water in the Morning – Plants’ roots are more receptive to watering in the morning and the evening and less so in the midday sun.  Watering in the morning gives the plant time to absorb the water and get ready to handle heat, cold, or just the energy it takes to produce chlorophyll, grow, and move nutrients around.  However, it’s not a good idea (if you can prevent it) to water in the evening, because when you let water sit on the leaves overnight, your plant is more likely to contract some plant diseases, like mildew, mold and all kinds of disease problems. The leaves should have time to dry before the sun goes down.  It’s much more difficult for plant diseases to get foothold when the foliage is dry.  Plants are closed up tight to retain water when in direct sun, and you waste the most water. That said, if you get home from work and your plants are dry, even if it’s in the evening, give them a good long drink.

4.      Water Deeply, Thoroughly and Infrequently – The most important thing when watering plants is to give them a good, long drink.   You do this because many of the plant’s roots will be down towards the bottom and you want them to be able to get water too.  It will also encourage roots to grow further down which is better for plants.  It’s important to wet the ground heavily rather than to just sprinkling a little water which can make the soil look damp on top while remaining dry underneath.  Your goal is to create soil that’s damp but not soggy down to five to six inches below the surface.

5.      Know Your Plants – Most plants prefer to live in moist soil, not wet, just damp.  However, different plants have very different moisture needs. Some plants like to be dry, some like to be a bit dry between watering and then there are those princessy plants that, if they get even a little dry, will swoon and drop all their buds and leaves. However, as a rule of thumb, flowering annuals don’t like to get too dry. Succulents like to be a bit dry and vegetables – particularly those that are juicy (tomatoes, cucumbers, melons) – like to be kept moist and need a huge amount of water. Some herbs (basil, rosemary, thyme, dill, oregano, cilantro) like to dry a little between watering and the flavor will be stronger if they do.  Some herbs like (parsley, sage, chives) like more moisture.  One way to keep track of your plants’ watering preferences always nearby is to keep the plant tag, either under the pot or buried in the soil.

6.      Don’t Rely on the Rain – Even if you think that a rain shower has watered your plants, check anyhow.  Sometimes a plant’s foliage and flowers can act like an umbrella and actually keep water from getting to your soil – shedding the moisture right out of the container.

7.      Don’t Assume Once is Enough – Don’t be surprised if you end up having to water your planter more than once a day.  Heat, wind and dry air can quickly parch your plants.  Terra cotta pots, hanging baskets made from coir and metal pots all can dry our ridiculously fast on a hot, windy summer day.  Over the season, you will probably get to know which containers need to be checked more than once a day, but when they are first planted, it’s a good idea to check your containers in the morning and again in the afternoon.

8.      Use the Right Tool and Water Gently – For efficient watering at the root zone, water gently, with a rose (like a shower head) which will damage the soil less than a jet of water and prevent much mud splashing up onto the leaves.


A Good Rule Of Thumb:

The best rule of thumb is to water as deeply and as infrequently as possible. Watering to make sure the soil is moist to at least 6 to 8 inches (15 to 20 cm) deep is best because it helps the plant grow its roots deeper into the soil.  A note here:We don’t mean to flood your plants!  Just a good deep watering, don’t get carried away.

Frequent light watering is not good for your plants because it only wets the surface of the soil which encourages roots to grow upwards in search of moisture. The water evaporates quickly and the soil dries out, leaving the roots in hot, dry soil.


Three Watering Mistakes:

1.       Watering the leaves and flowers, instead of the ground at the base of the plant.

2.      Watering at midday.

3.      Watering while naked.

Tips via DIGS Vancouver