It happens: you get a beautiful flat of healthy, robust strawberries or a towering raspberry from the nursery or home improvement store, and you followed the instructions to the letter on the tag. But it's still withering and dying, turning crispy on the leaves and looking...puny. What did you do, you monster?
While you may be tempted to give your plants MORE water...DON'T! They are going thru the hottest part of the year right now, and this is a form of "sunburn" or "heat stroke". No amount of water is going to save them. In fact, it may end up killing it completely! Right now, you still have a chance at saving these babies.
First off, why is this happening? Well, let's consider this. Your skin is less than an inch thick. What happens if you stand out in the sun for even 60 minutes at a time? You look like a lobster that's been boiled, right? It's the same for plants. Just because it says "full sun", doesn't mean you stick it DIRECTLY in the sun. The suggestions on the care tag that comes with the plant are for ESTABLISHED plants. Not the guys you bring home in pots or containers. Those are typically less than a year old, and don't quite have the root system to handle that kind of pressure. They're just getting started.
Even if the tag says "enjoys full sun", you're going to want to plant her in partial shade for the first year. This way, her roots get established and she's plenty healthy and strong for the upcoming scorching weather. If you just plop her down in a bare patch with no shade, mulch or other plants to off-set the ungodly heat, she's gonna end up sun scorched. Tender, young leaves can't handle our high desert climate. Between wind burn, sun burn and nutrient burn, there's an awful lot that can end up burning your plants. Let's look at these individually and determine the ROOT cause of your problems.
Wind causes damage to the leaves of a wide range of plants by shredding them. Leaves can also suffer wind scorch (leaf scorch), where they wither, with a scorched look, with brown or sometimes black coloring either on their edges or over more-or-less the whole leaf. The leaves turn dry and brittle and may fall off. To protect your plants from this, make sure there's an adequate wind break or barrier that will prevent the leaves from getting whipped around by our monstrous wind speeds that can blow through the Treasure Valley. Pine trees are a wonderful form of wind break that thrive in Idaho. Their needles aren't as susceptible to wind damage as tender leaves are. Arborvitae is another great choice, albeit somewhat messy during the "shedding" times. They also are known to harbor pests that will eat your plants, as well as "weeping" of sap, if not cared for properly. They do have their benefits, however, as they are aesthetically pleasing when kept neat and well cared for by a professional landscaper or arborist. Arborvitae also need to be planted at the correct time, or they WILL turn brown and crispy and die completely. Very finicky plant when first starting out. You MUST baby your plantlings the first year, regardless.
Nutrient burn or fertilizer burn is one of the most common beginner growing problems. The yellow or brown leaf tips are caused by too-high levels of nutrients at the roots, which disrupts the flow of water through the plant and causes the symptom of burnt tips on leaves. Basically, too much of a good thing, too soon. You really don't want to fertilize for the first year. If you're following proper planting instructions, you're going to be using a good top dressing to provide all the nutrients they need instead of needing to add these to the soil. I promise, the soil you use (provided it's a good quality) will adequately feed your plants for the first year, without a need for additives. If you're worried you may have done this, and are noticing signs of nutrient burn, you can attempt to "flush" the roots of all nutrients by excessively watering your plants with water at a pH level between 6.0-6.8 for soil and 5.5-6.5 for hydroponics. Fully saturate your pots, and repeat 15 minutes later. The flush should clear any blockage and make room for new nutrients. Soil flushing is a technology used for extracting contaminants from the soil. It works by applying water to the soil and essentially "rinsing" the roots. The water has an additive that enhances contaminant solubility. Contaminants that are dissolved in the flushing solution are leached into the groundwater, which is then extracted and treated.
Also referred to as heat scorch, sun scorch and sun scald, it's all the same: they're getting too much sun. As we mentioned above, it's like sitting out in the sun yourself without any SPF. Plants are no different. Sunscald injury of plants is easy to prevent, though there is no cure. Once leaves are damaged, all you can do is support the plant until it manages to grow new, stronger leaves. Prevention is the best protection when it comes to your plants. for treating Heat Stress, place temporary shading, such as shade cloth, or pop-up canopy for larger areas, over plants to keep them cool and block out the sun's rays. Deep water plants first thing in the morning, if possible. Do not fertilize during times of heat stress (see nutrient burn above). New growth is especially susceptible to the effects of heat.
5 tips for preventing sun scorch and heat stroke in plants:
1. MULCH, FOR SO MANY REASONS We cannot stress the benefits of mulching enough around here at Emerald Ladder. Direct sunlight can wreak havoc on your plants, but mulch – especially reflective kinds such as dry grass clippings – can be a plant-saver. It also reduces maintenance chores, saves water by retaining water and reducing evaporation, and encourages vigorous plant growth. This means less watering for you and happier, healthier roots. And the best part is that savvy gardeners can find everything they need for a good mulch without ever spending a dime. Other mulching options include straw, alfalfa, newspaper, black plastic sheeting, and even seaweed. Here is a helpful list of mulch variations that can be used for all temperatures and conditions. 2. EARLY MORNING WATERING Drinking water first thing in the morning has been shown to provide a range of health benefits for us. And the same goes for our plants. Heat waves can quickly pull the moisture right out of soil and dehydrate shallow roots. Watering early in the morning ensures that roots are amply hydrated before the oppressive heat of the day begins. This also prevents heat stress, which is basically sunburn for your plants that occurs when the sun gets to its apex and plants’ leaves are just too brittle to fight off the sun. A second watering is never a bad idea if just one isn’t doing enough. An 11am watering, provided the Heat Index (HI) isn't too high for that day, should give your guys the oomph they need to get through the mid-day heat stretch.
3. SHADE CLOTH AND ROW COVERS: Another way to prevent heat stress and protect your crops from the direct sunlight is a shade cloth or row cover. There’s a range of options available, ask our professional landscapers what they recommend. Just make sure your garden can still breathe and grow. If you cover plants too closely, helpful insects such as bees won’t be able to work their magic and heat will get trapped and defeat the purpose of shading in the first place.
4. LET ESTABLISHED PLANTS TAKE TRANSPLANTS UNDER THEIR WING: An alternative to shade cloths or row covers is to plant transplants under the cover of stronger plants with established root systems. To return to the human/plant analogy, heat waves hit the youngest and oldest among us the hardest. This anecdote works just as well for plants. At least partial shading will go a long way to ensuring young plants don’t get scorched by direct sunlight. But make sure that the transplant still gets partial sunlight as permanent shade is just as deadly for a young transplant. Also, make sure you're not planting them too closely together, as the larger plant will leach the nutrients out of the soil, starving the younger plant. Definitely seek advice from a professional in terms of adequate spacing so they don't get choked out.
5. PLANT SEEDS SLIGHTLY DEEPER: If you get a late start to putting down seeds or live in a place that is warm year-round, plant seeds a bit deeper than you normally would. In the springtime, early morning and night temperatures are dramatically cooler than daytime temperatures but the temperature gap narrows during the dog days of summer. Warm temperatures and direct sunlight can dehydrate topsoil in no time. Planting a seed an extra inch or two deeper will allow the root systems to avoid being choked and dried out if this occurs. Those first warm days of spring are a welcomed sight (and feel) for us gardeners. But gardening in the dead heat of summer can be a balancing act. With these tips, you can recognize and avoid heat stress in your plants and keep them safe, healthy, and happy. And remember, you’re also at the mercy of the sun. It is wise to avoid strenuous outdoor work when both the temperature and the humidity are high. As a rule, when the two numbers added together equal more than 160, stay indoors during the middle of the day.
The bottom line:
Fresh from the store plants need all the protection they can get. Whether it's a strawberry plant or a towering root ball tree, they need to be protected in this heat, and from the suns extreme UV rays. Protect your investment.
As always, if you're unsure or need help, give us a call and we will help you take care of your tender, young plants.
Stay cool this week, everyone. Triple digits are just as hazardous for your health, no matter how much you enjoy the heat.