As the thermometer continues to soar past 85°F, with a paltry 1/10 inch of rain in over a month, our homestead is starting to feel like the Sahara desert. And yes, it’s still spring! We’re nestled in the foothills of the mountains, where temperatures were once more agreeable. However, we’re experiencing an unprecedented stretch of hot days, far exceeding what’s typical for our climate.
The heat wave starts earlier in spring and lingers longer into fall, effectively shrinking our window for growing cool-season crops safely. Moreover, high temperatures are making it challenging to start some warm-season crops. There are numerous hidden complications arising from premature heat streaks as well. As homesteaders, we’re accustomed to thinking about season extension to get a head start in spring or extend the growing season into fall and winter.
Now, it’s time to flip the script and explore ways to prolong our cool season too! We must adapt and find creative solutions to overcome these challenges and ensure a bountiful harvest.
Heat Can Be a Big Problem For Gardens
When early season heat waves strike, many gardeners face a significant challenge. One major issue is the increased likelihood that cool-season plants will bolt, or start flowering prematurely, due to unseasonable temperatures. However, this is just the tip of the iceberg. Even if you can prevent bolting, your plants are still susceptible to a range of heat-related problems that can be difficult to mitigate.
For instance, excessive heat can severely impede photosynthesis and transpiration – two crucial processes necessary for plant growth and development.
Photosynthesis Failure
While plants use the sun’s energy, water, and carbon dioxide to produce their own food through photosynthesis, this process is not immune to the effects of heat. In fact, short-term heat can cause plants to temporarily halt sugar production without causing permanent damage, akin to humans taking a nap on a hot day. From a gardener’s perspective, plants may appear to stop growing during extremely hot days, with no new flowers forming and foliage remaining healthy but not increasing in size.
This reduction in photosynthesis can lead to later harvest times, but it is not typically a major concern. However, prolonged heat can have more severe consequences for plant growth. If plants are exposed to excessive heat for an extended period, they can suffer irreversible damage to their ability to produce sugars through photosynthesis. Some critical systems begin to fail under the pressure of repeated hot days, leading to reduced growth and development.
The heat tolerance threshold varies among different plants, with cool-season crops generally being more sensitive to heat than warm-season varieties. For example, young warm-season plants tend to have a lower heat tolerance than mature plants. If heat stress occurs during critical development phases, it can result in weak root systems, deformities, or stunted growth due to impaired photosynthesis.
Transpiration
When primary systems falter, secondary systems often follow suit, exacerbating the situation. In humans, lung problems can lead to heart issues due to inadequate oxygenation. Similarly, when plants’ transpiration process falters, it can have devastating consequences. Transpiration is akin to a plant’s equivalent of breathing and sweating combined – it involves absorbing water from the soil, using some for hydration and cooling, while releasing excess moisture through leaves.
This process is essential for regulating temperature and humidity around the plant. However, as photosynthesis declines, transpiration increases, placing a high energy demand on plants that they may not be able to meet. As heat-stressed plants struggle to cool themselves, their ability to regulate temperature further deteriorates, setting off a vicious cycle.
Soil Life Risks
When plants transpire heavily, they remove water from the soil, causing it to dry out and heat up in response. This increased warmth triggers microbial life in the soil to rev up their decomposition processes, breaking down added organic matter at an accelerated rate. The combination of faster decomposition rates and plant uptake rates can deplete your soil’s fertility reserves, leaving you with a negative balance sheet.
As plants begin to struggle and organic matter is consumed, soil structure also begins to degrade due to drained water stores. This can result in the loss of a previously cultivated loam-like texture, making it essential to strike a balance between plant growth and soil health.
Simple Summer Solutions
While it may seem daunting to manage your garden during consistently hot weather, there’s hope! To thrive in these conditions, focus on regular and deep watering of your plants. Additionally, prioritize growing heat-loving species like maize, amaranths, millet, and sorghum, which can provide much-needed shade for other warm-season crops. By incorporating these C4 carbon fixation plants into your garden, you’ll be able to maintain a healthy soil condition throughout the summer.
The key challenge lies in navigating the transition period when cool-season crops are still maturing and hot weather sets in. Fortunately, I’ve discovered a few strategies that can help you successfully manage this situation and keep your garden thriving.
Cool Season Crops Extension in Hot Weather
While extending a cool season into hot weather presents distinct challenges, there are commonalities with creating warmer conditions in cooler climates. A key similarity lies in leveraging plant selection, strategic mulching, and seasonally-appropriate coverings to regulate the temperature and create a more hospitable environment for your garden.
Tip 1: Grow Heat-tolerant Cool Season Crops
When you’re gardening in an area known for scorching early spring days, it’s crucial to select cool-season plant varieties that can withstand extreme temperatures. Look for seeds labeled as slow-bolting or heat-tolerant, as these have demonstrated greater resilience to heat fluctuations. Conversely, opt out of planting long-season cool-loving varieties altogether, unless you’re planning for a fall sowing.
For instance, fast-maturing cabbages like Early Jersey Wakefield, Golden, and Red Acre exhibit more heat tolerance than their slower-growing ballhead counterparts. Similarly, broccoli tends to perform better in hot weather compared to Brussels sprouts. If you prefer cauliflower, smaller heading varieties or purple ones work better than giant white heads.
Interestingly, cool-season crops grown for their flowering heads, such as broccoli raab and Chinese kale, continue to thrive in hot conditions. Kale and mustard generally fare better in heat than many other cool-season crops.
Tip 2: Grow Baby Size Vegetables
When temperatures soar above 85°F, certain crops like Chinese cabbage are prone to bolting. To avoid this, plant multiple rows and harvest them at half size. This will encourage you to get your warm-season crops in the ground sooner, taking advantage of the newly turned beds.
In addition to Chinese cabbage, other varieties that thrive when harvested young include baby turnips, half-sized daikons, and Pok/Bokchoy. For a bonus, consider harvesting baby peas early in the summer.
While it requires a bit more effort than waiting for full-size peas to mature, the reward is worth it.
Tip 3: Higher Planting Density
When plants are grown in close proximity, they create a microclimate that offers shade to the surrounding soil. Additionally, they share the benefits of evaporative cooling through transpiration, which helps to regulate the temperature. This type of dense planting requires careful maintenance, including high levels of soil fertility, regular harvesting, and prompt responses to pest problems.
It’s not a low-maintenance gardening approach, but with proper care, it can provide numerous benefits, such as increased heat resistance and enhanced soil protection. By mastering the art of maintaining soil fertility, you can successfully cultivate multiple plants in a small space, ultimately achieving a more resilient and thriving garden.
Tip 4: Mulch Appropriately
Using various types of mulch can help regulate soil temperature by retaining moisture. In scorching weather, however, a lighter-colored mulch can be particularly effective in reducing the amount of radiant heat absorbed by the soil. This is analogous to how wearing light-colored clothing keeps you cooler than dark attire. Similarly, covering dark-hued soil with a light-colored mulch like straw or even white row cover material can provide relief from the heat.
Instead of using it to cover plants, consider laying it directly on your beds in areas where exposed soil is present, such as between rows or in open spaces where germination is just beginning.
Tip 5: Provide Mid-day Shade for your Cool Season Crops
While a narrow grape arbor provides welcome shade to rhubarb, many vegetables require a minimum of 6-8 hours of sunlight per day to thrive. However, it’s not necessary for that sun to beat down on them at its strongest points. In fact, row covers placed directly above plants can offer relief from the midday sun. Since the sun follows an arc across the sky, plants still receive ample sunlight during other parts of the day.
To create your own natural shade structures, consider using shade cloth or weaving together natural materials like twigs and leaves.
Tip 6: Provide Afternoon Shade for Your Cool Season Crops
Incorporating natural or artificial shading elements into your garden design can have a profound impact on the health and productivity of your plants. Kiwi vines and trellised tomatoes are excellent examples of how you can create shade for other rows, allowing them to thrive in conditions that would otherwise be too harsh.
While most plants benefit from good morning sun, it’s equally important to provide late afternoon shade if direct overhead sunlight isn’t feasible during the hottest part of the day. In my own garden, I’ve noticed that creating a shaded area by 4:30 pm each day using our surrounding woods has a significant impact on soil temperatures and overall plant performance.
By cutting out about two hours of intense heat, I’m able to grow a wider range of crops, including lettuce, turnips, mustard, kale, and cabbages, which would normally require a more Northern climate. To achieve similar results in your own garden, you can utilize tarps, hedges, fences, trellised plants, and other creative solutions to create afternoon shade and extend the growing season for your favorite varieties.
Tip 7: Water Your Soil
While drip irrigation is touted for its efficient watering method, targeting plant roots directly and minimizing soil saturation, this approach may not align with organic gardening practices. In fact, maintaining a healthy living soil requires keeping it consistently moist, especially during hot weather. This is because the ideal soil structure consists of approximately 25% water content at all times.
To achieve this, gardeners should strive to keep their entire soil volume hydrated, rather than focusing solely on root zones.
Tip 8: Use Your Weeds
While it may be tempting to eradicate weeds that seem to sprout from nowhere, consider their role as nature’s emergency mulch. Barnyardgrass, spurge, and purslane are just a few examples of weed species that can alert you to underlying soil issues, such as compaction and desiccation. As opportunistic invaders, they help prevent irreparable damage until conditions improve. If an abundance of weeds appears, it’s likely a sign that your organic matter is depleted and the soil is too dry.
In this scenario, incorporating more fertility and watering generously are essential steps to restore balance. I personally don’t immediately remove these beneficial weeds from unplanted areas or pathways, allowing them to protect the soil until I can add additional compost or introduce alternative cover crops. Instead, I focus on controlling their spread around specific plants to ensure they don’t outcompete my preferred flora.
Tip 9: Add Compost More Often
While many gardening experts advocate for adding compost in the fall to yield optimal results, this advice only holds true when using immature compost. In contrast, well-aged compost (at least six months old) can be incorporated into your garden at any time of year. This approach offers several benefits. For instance, consistently applying well-aged compost as temperatures rise can help maintain a healthy soil condition during heatwaves.
By doing so, you’ll reduce plant stress by providing a steady supply of nutrients and also improve soil water retention when sufficient amounts are applied.
Tip 10: Use Liquid Fertilizer
In addition to mulching and using organic matter, another effective way to ensure plants receive essential nutrients during hot weather is through the strategic application of liquid fertilizers. Unlike traditional methods where the soil serves as a nutrient reservoir, liquid fertilizers can provide an ’emergency IV’ to stressed plants and soil. Compost tea, fish emulsion, or even urine can be used to give plant roots a much-needed boost when temperatures soar.
As long as these liquid formulas are formulated with a balanced 3-3-3 ratio of nutrients (or lower), they won’t disrupt the delicate balance of soil life for short-term use.
Long-Term Tips for Cool Season Crops
Beyond implementing simple cooling techniques, there are several long-term strategies that can help your garden thrive in the face of extreme heat. While these methods may require a bit more research and planning upfront, they can pay significant dividends if you’re consistently dealing with scorching temperatures. By exploring these options, you’ll be better equipped to create a resilient garden that can withstand even the most intense heat waves.
Tip 11: Slope Your Beds
The optimal placement for kale and cabbage in a hugel bed is actually on the north side, where they can thrive in the warmth. This is because the way sunlight hits the earth at an angle during certain times of day disperses light energy more evenly. By incorporating gentle slopes into your garden beds, you can reduce the direct absorption of radiant heat and subsequently lower soil temperatures slightly.
However, it’s essential to consider that slopes also introduce new challenges, such as excessive drainage, which requires a comprehensive plan to overcome.
Tip 12: Consider a Misting System
By harnessing the power of misting during peak heat hours, gardeners can significantly reduce the need for plants to engage their natural cooling mechanism – transpiration. This simple yet effective technique, when combined with good watering practices, can prove instrumental in keeping plants from entering the heat stress zone, where a cascade of problems often unfolds.
Beat the Heat
While it’s not possible to salvage all cool-season crops from the heat, the following tips will significantly boost your garden’s heat resistance. However, even with these precautions, there may be years when extreme temperatures still threaten your crop’s survival. To prepare for such instances, have a plan in place for rotating your crops early and maintaining soil cover using high-heat germinating cover crops.
Additionally, keep a stash of herb-infused water or homemade lemonade on hand to help you stay cool and focused while working to maintain healthy soil conditions.
