Gardening in the Heat – Garden Update, June 29

41C! (105.8f). Yes, 250m from the Pacific Ocean, 15m elevation and we recorded 41C Monday, June 28th and 40C the day before. We all know what this has meant for us, for water-use, and electricity; for health and safety, but what has it meant for the Garden?

Well, I have no pictures to show today because I avoided the garden for the last two days. But one potted plant and one of my hops is showing signs of “burnt” leaves. The leaves are pale, curled and crispy-dry. I’m fortunate it’s only two plants, since many are reporting large die-off in their yard. Here’s what you need to know:

Unless plants are way out of their natural environment, air temperature rarely kills plants. It is the root temperature that can both cook a plant and freeze it. One of the plants I have lost is in a pot. The pot, being entirely exposed, likely hit temperatures of extreme, maybe being higher than air temperature due to the sun exposure on the black pot. The plant cooked. The hop is in its first year in that spot and it has about 1.5feet square of soil (mulched with drain rock) and surrounded by concrete. The concrete, the south facing wall and the overnight temperatures staying above 20C (70f) have likely stressed the plants root system to the point to showing “burnt” leaves. Similarly, (at a different time) my Rosemarys planted in the ground have survived -8C, but those in pots froze to death at a prolonged -4. Root exposure is the culprit.

So, to keep your plants alive and healthy in hot, blazing sun, you need to water deep and mulch. It really is that simple. I currently water a lot, but only because I’ve watered too little in previous years. I’m trying to find a happy medium between major yield losses and wasting water. I’m happy with smaller fruit with dense flavour, but I’m not happy when plants shut-down or die. In raised beds, it’s been important for me to have two waterings per day. The reasoning is to get water deeper. When you water dry soil you see it struggle to absorb. Some of it beads, or runs to a low spot before slowly soaking in. When soil is wet, additional water seeps immediately into the soil. This, occurring regularly is how water can get deep enough to be available to plant roots at a cooler spot.

Remember: you can grow plants in pots, but they prefer soil depths of two feet or more. The deeper the roots the healthier the plant and the better able it is to survive swings in temperature and moisture.

When watering for depth, try this: Give your entire garden a once-over with the hose. Ensure a “shower” setting gets the entire surface wet. Do this enough before water settles on the surface, even for a moment. At that point, move on to the next area. Likely, by the time you finish the yard, return to where you started or wait a few minutes to ensure 10 minutes or more has passed. Now water again with the shower setting, applying more water than before, but stopping anytime it collects at the surface. Depending on your soil type, this can get water several inches down. An easy way to test is to make a hole with a small shovel and see where the moisture ends. This watering can be repeated as necessary.

Evening escaping the heat.

If you have large trees nearby, especially firs or other heavy water-users, you may find your yard takes a ton of water to get the soil moist. Some trees can deflect light rain fall and keep it from your garden, but they also absorb so much from the soil that you can actually be drying from below. In spaces like this, it is important to put a barrier between your soil and the natural soil to prevent this.

Otherwise, soil dries from the surface. So daily deep watering will continue to get deeper as long as more is being applied than is being evaporated or used. The best way to keep evaporation low is to mulch.

There are a ton of mulch options, and all have pros and cons. I use a straw specifically chopped fine (with weeds removed) for mulching. This straw has the added benefit of being bright, and even shiny, which means it reflects some light: good for plants and good for keeping sun off the soil.

Of course, some plants love the heat: corn, grapes, squash, peppers for example. So, dark mulch may be best for those areas. However, the same rules apply. They might like hot air and maybe hot roots, but consistency is best. So regular water and ability to send deep roots is still best.

How about the bugs, you ask. Simple. They are fine. Especially in low wind, plants’ transpiration creates micro-layers of high humidity directly on the surface of leaves and especially below. Invertebrates like mites desiccate when vapour density is low, and so will hide in these spaces, especially in pockets of leaf tissue, like along the veins. The temperature itself is rarely an issue as long as the increase is gradual enough for bugsto seek shelter and prepare. Sometimes eggs or other vulnerable life stages can succumb to dry heat, but populations recover. Others, like bugs in the soil, simply go deeper, or below plants to ride out the heat. As you may have noticed, if you braved the heat to check the garden is that little was moving in the middle of the day. In the stillness of our 40C air, I saw nothing but butterflies (and cabbage moths) in the garden. The rest, even foliar insects, would have just stayed in the densest, most protected parts of their respective plants to await for better conditions.

On to the garden!

Bed 1: Blueberries

So far, so good. The heat has shrivelled a few, but others are still looking big and fat. I added sulphur to the surface to lower ph, and mulched again, then built this frame to hold netting to keep the birds off the plants. Notice the amount of bare ground: after companion planting for years in a row I have decided to give the blueberries some breathing room in hopes of getting healthier plants. While there are berries this year, there is still minimal new growth.

Bed 2: Raspberries

Looking great. If they had ripened prior to this heat wave we would have done a better job of picking them. I feel like we’re wasting them right now, as ripe ones are being eaten by lizards and birds.

Bed 3: Strawberries

Just like last year, the berries have taken a summer vacation. Fruit was hard to keep up with and suddenly (despite flowers and emerging fruit) there is nothing ripe at the moment.

Bed 4: Asparagus

One of the asparagus has fruit again. I’ll plant these to continue to fill the bed. The Rhubarb suffers here in the hot, dry soil of this bed. They will be moved to a permanent spot this year – I hope.

Bed 5: Onions

Onions love the heat. I seem to have a couple carrots going, and the garlic appears to be almost finished.

Bed 6: Determinate tomatoes

Very compact bushing from the Romas, so my attempting to tie them isn’t having the affect I want. The “semi-determinant” “Tasti-lee” send runners out which are easier to tie. These might work-out. The poppies struggle in the heat and have been a magnet for the black aphid – but that aphid can’t spread to the tomatoes, so I’m happy attracting predators to this garden.

Bed 7: Beets

All of this is doing well. I’ll replan it to make better use of the space, but we’re pulling beets and enjoying them!

Bed 8: Garlic

Almost done. Most scapes have been pulled and a few peppers have taken the place of the celery that bolted from the year before.

Bed 9: Misc

Favas are finishing (to be kept for winter sowing). The parsnips that I tried to sow below them are non-existent. We’ll skip them this year. It was dry, and just like the carrots in the next bed over, something eats all seedlings this close to the fence line. My wife added some flowers and I tried a few more onions but also decided to try the cannabis here, since it was unused space.

Bed 10: Flowers

Boom! They look fantastic. The heat is hard on some, but others love them.

Bed 11: Flowers

More of the same.

Bed 12: Wheat and Corn

This bed is fantastic. The hot weather may be perfect for the wheat, as the grains are large and beginning to dry. The hot weather also made the corn shoot-up. These photos were taken on the solstice, and growth has nearly doubled one week since. The corn today is twice the height of the wheat.

Bed 13: Misc

Corn here is smaller, but there are mixed varieties. The bit of barley that came up is struggling in the lack of water below the fir.

Bed 14: Brassicas

Some finished early. Others are looking great. But the star is probably the flax.

Bed 15: Mustards

It looks ugly now. The seeds are developing so I can’t cut it out yet, but it’s entirely finished soon. With some cooler weather more arugula and mustards will be planted along with rutabagas.

Bed 16: Indeterminate tomatoes

My pattern of taking each variety and growing with one, two or three leaders has continued. There is no clear-cut winner, and I suspect it may come down to variety. Plus, with the small sample size I can not account for variations seed to seed. However, I have noticed that those with one leader are more likely to send new leaders out from the base. Potatoes took a beating by the flea beetle, but I just left them alone. They look fine now. Let’s hope the larva aren’t affecting the tubers.

Bed 17: Lettuces

Still going! I don’t know if it’s the shade this bed gets or what, but romaine are still at a cut-and-come-again stage, but could be cut as head lettuce. Some icebergs could be cut as heads, but are also still doing fine. The resowing of lettuces has not done well, since they dry too quick and it’s too hot to keep them long in pots. Sweet peas smell enchanting and the other peas will likely finish soon, but have been incredible in production.

Bed 18: Brassicas

Cabbages and brussels look good. Broccoli never caught up, and some small heads are about to bolt. I’ll investigate further. Sunflowers love this weather!

Bed 19: Peas and Beans

The peas grew so well that they have shaded the other parts of the beds. The black beans (middle) have hardly come up, and the chick peas do better towards the south of the bed, where they get more light. This bed needs a redesign.

Bed 20: More corn and wheat.

Same as bed 12, the heat has helped. Wheat looks good, corn looks great and the pole beans are climbing the corn!

Top Garden:

Squash. They love the heat and are taking over. We still need to address the grass that can choke out smaller plants. We’ll save that for a cooler day.


Nothing there.

Sowing Schedule:

Nothing for a while. Brassicas, rutabagas will come soon, as well as regular sowing for carrots, beets, arugula, mustards and lettuces, when the normal weather returns.

The stand:

We’ve found it too hot to pick. So peas and berries are being wasted. Fresh greens have continued to do well. The fresh celery we placed at the stand never sold. So after the first year selling heads of celery for $6 and not having enough, we have failed to sell any since then. Organic celery is such a rarity, we’ll keep growing it for ourselves. But we don’t need much unless we chop and freeze it. The flowers always do well….so well that I keep being pressured to drop another veg bed to make way for flowers. We have high hopes for tomatoes. We know those sell, and we still eat and preserve plenty. This year we are really focused on finding the best flavour and keeping those seeds.

See you soon!

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