attract beneficial insects – Sustainable Market Farming

Insectary flowers to attract beneficial insects

Sunflower bee and bug. Photo by Bridget Aleshire — Sunflower bee and bug. Do you know this bug?
Photo by Bridget Aleshire

As part of our strategy to entice pollinators and other beneficial insects into our garden, we plant selected flowers among the vegetables. On a big scale this is known as Farmscaping, and you can read about it in a publication from ATTRA; “Farmscaping to Enhance Biological Control – IP065” It’s 99c for the download unless you are a subscriber, or if the cost is beyond your budget. Oregon State Extension has a 40 page year 2000 version online.

We plant Sweet Alyssum with our spring broccoli and cabbage to attract insects that prey on aphids. This works very well. We plant one Alyssum plant per 8 broccoli or cabbage plants in the center-line of the bed, between the two rows of brassicas. We sow it in the greenhouse in early March, around the time we sow replacement broccoli and cabbage, and transplant in mid April when we do the gap-filling, replacing any brassica casualties, 2 or 3 weeks after transplanting the brassicas. We have to explain carefully to our helpers not to weed them out, or smother them with mulch when we move the garlic mulch over to top up the brassica mulch.

As you’ll see in some of the photos, we do also grow some repellent flowers (nasturtiums, french marigolds) and some trap crop flowers (cleome for harlequin bugs) but I’m not going to talk about those today.

Insectary circle at the end of a bed of chard. Photo by Bridget Aleshire — Insectary circle at the end of a bed of chard.
Photo by Bridget Aleshire

Plants with small flat open flowers, like alyssum, dill, yarrow, buckwheat, sunflowers, cosmos can attract ladybugs, lacewings, aphid parasites, damsel bugs, braconid wasps, rove beetles, syrphid flies, and spined soldier beetles. This is a rather loose and general statement. you can read the ATTRA publication to make a specific plan to tackle particular pests. Ladybugs are a good general help because they eat the eggs of many different pest species.

At the end of April we sow several plug flats of different flowers to plant out in Insectary Circles at the ends of our raised beds. We include borage, dill, calendula, cosmos, sunflowers zinnias and tithonia in that sowing, and hope to plant them out in mid-late May, after the big push to get all our tender transplanted crops out. We used to sow earlier, but we find ourselves too busy to get them transplanted at the right stage of growth, so it’s better for us to hold off and sow later.

Insectary circle in an okra bed. Photo by Bridget Aleshire — Insectary circle in an okra bed.
Photo by Bridget Aleshire

We choose beds where the crop will be in place for a long stretch of time, hopefully to the frost date. This includes tomatoes, eggplant, okra, chard, leeks. Because our focus is on food crops and we are always too busy, we have evolved a method that uses little time and reduces the chance of things going wrong. As mentioned above, we get a lot of help in the garden from visitors and people who help out for half a day a week, so we need to make the flowers obvious to prevent over-zealous weeding. The main way we do this is to take old plastic buckets and saw hoops from them. We set the hoops in the soil and plant he flowers very close together inside the hoops. This marks them out as something special. And it really works fine to have the flowers just 2 or 3 inches apart.

Insectary flower planting day is ideally one when rain is expected at night, as otherwise it’s a fussy job to tour all the circles with a watering can every day. We take a wheelbarrow and set the flats leaning out the sides like wings. Some kinds of watering cans can be carried on wheelbarrow handles. that helps. The hoops can also go on the wheelbarrow handles. Then we work our way along the driveway, finding suitable beds. We dig with a trowel to make a circle big enough to set the hoop in, and pile any extra soil inside. Then we plant a selection from our flats, water and move on.

After the driveway, we work along the center path between the east beds and the west beds and then back along the east side, where there is a path. We hope to find a suitable spot every 25 feet or so. if it doesn’t rain, we do hand-water daily until each circle has had a good soaking from night-time sprinklers or rain.

We haven’t made a scientific study of whether these flowers do attract more beneficial insects than we had previously, but we do enjoy seeing the flowers, and I firmly believe that diversity of species helps the ecosystem.

Borage in an insectary circle. Photo by Bridget Aleshire. — Borage in an insectary circle.
Photo by Bridget Aleshire.

Planting spring broccoli, farmscaping, BMSB

Flats of broccoli seedlings in our cold frame. Photo Kathryn Simmons — Flats of broccoli seedlings in our cold frame.
Photo Kathryn Simmons

We’re mid-way through transplanting spring broccoli. It’s been a challenging “broccoli-planting season” with two very cold nights (20F and 22F) since we started, some high winds (very cold and drying, hard to keep the rowcovers in place). In order to have as long a broccoli harvest period as possible, we use several varieties with different days-to-maturity, and do two sowing dates. This spring we are using the following varieties:

**Tendergreen broccoli Credit Fedco Seeds**

Tendergreen (47 days from transplanting),

Green King broccoli Credit Fedco Seeds — **Green King broccoli**
**Credit Fedco Seeds**

**Green Magic broccoli Credit Johnnys Seeds**

Green Magic (57 days), Green King (65d), Arcadia (68d) and Diplomat (also 68d).

**Arcadia broccoli Credit Johnnys Seeds**

**Diplomat broccoli Credit Johnnys Seeds**

These are all varieties we’ve grown before and had success with. Tendergreen is exceptionally fast, and gets us off to a good start. It’s not heat tolerant, however.

Note that the catalogs give different days to maturity. Sometimes these are from sowing. We’ve calculated our own for comparison.

We sowed our first round of broccoli on February 10 to transplant April 4, and our second round (a repeat of the first) on February 24 for transplanting April 10. For insurance we do a (smaller) third sowing of the two fastest varieties on March 6 to fill gaps on April 25. Well, the plants in the flats looked great! We delayed the start of transplanting because of the weather. We transplanted on April 4 and April 9. The first planting suffered from the two very cold nights I mentioned, even with thick rowcover. So last week we replaced casualties with plants left over from the initial planting. (We spot out 20% more plants than calculations say we need.) We had 20 flats of 40 plants for each of the two plantings. Today we will plant the second half of the patch, over a week later than originally planned.

The third sowing has been in the cold frame for about a week. We like to give them two weeks to harden off. In another week we’ll go through and replace casualties throughout.

Sweet Alyssum Credit Southern Exposure Seed Exchange — **Sweet Alyssum**
**Credit Southern Exposure Seed Exchange**

At the same time we’ll transplant Sweet Alyssum in the centers of the broccoli and cabbage beds, about one plug every 6ft (it’s easiest to count 4 broccoli plants, then plant an alyssum). These little plants attract beneficial insects. You can read about Virginia State University research into Farmscaping. ATTRA also has a good publication.

Alyssum attracts the Syrphid fly and the Tachinid fly, predators of aphids and caterpillars.

We do other farmscaping too. We sow rows of sunflowers wherever we find space and nasturtiums with cucumbers and squash. We also transplant “Insectary Circles” with a mix of borage, cosmos, calendula, tithonia, dill, zinnias and cleome. We sow these in the greenhouse in plug flats in late April or early May and transplant in late May. If we had more time we could do it earlier. We found that sowing earlier was a mistake for us, as we don’t get around to finding time to transplant them until after the warm weather vegetables have been planted out. We choose beds with long season crops, (meaning ones that will be there a long time) to avoid problems trying to till around the circles. We cut bottomless circles from old plastic buckets, sink these in the soil at the end of a bed, and plant into them. This helps avoid the problems that can come with novice weeders!

Harlequin bug nymphs on spider flower (Cleome); note, white flecks in the leaf typical of feeding by true bugs Credit Missouri Botanical Garden — Harlequin bug nymphs on spider flower (Cleome); note, white flecks in the leaf typical of feeding by true bugs
Credit **Missouri Botanical Garden**

Cleome (spider flower) can be used as a trap crop for Harlequin bugs.(You still have to deal with the infested cleomes, but it keeps your brassicas free). The Missouri Botanical Garden has great info on Harlequin bugs.

Adult female brown marmorated stink bug. Credit Rutgers New Jersey Ag Station — Adult female brown marmorated stink bug.
**Credit Rutgers New Jersey Ag Station**

While one the subject of bugs and stink bugs in particular, I read some recent information on Brown Marmorated Stink Bugs in an eOrganic article on the eXtension site. They even have a video. The good news is that jumping spiders, ground beetles and earwigs have been observed eating the egg masses of BMSB, assassin bugs attack the nymphs, and the predatory spined soldier bugs eat both the eggs and the nymphs of BMSB. This is so much better news than the early days of the invasion, when it seemed like nothing would touch them.

But I don’t want to close with a picture of a pest, so here’s more broccoli. Yes, it’s under the rowcover!

Spring broccoli under rowcover. Credit Kathryn Simmons

Broccoli planting, hoophouse summer plantings, strawberry flowers

Spring broccoli plant one week after transplanting. Photo Kathryn Simmons — Spring broccoli plant one week after transplanting.
Photo Kathryn Simmons

We have at last finished planting out our broccoli – over two weeks late. The delays were due to wet soil preventing cultivation. Happily the plants were thriving in their 4″ deep wood flats. But it was tough to get them to thrive when transplanted that big. The weather was hot on most of those days, so we had to water a lot, even thought he soil was still saturated from the heavy rains.

Here you can see how we mulch our spring broccoli and cabbage: we make temporary raised beds, 4′ wide with one foot paths. then we unroll big round bales of spoiled hay over the beds and the paths too. They are just the right width for the bales. After that we make two rows of “nests” in each bed, using a measuring stick to get the right spacing. We use our hands to tease the hay apart down to soil level. Then we transplant, water in and close the hay over the soil around the stem of the plant. Then we cover with rowcover to protect from cold nights, bugs and stiff breezes. We use sticks to hold the rowcover down, rolling the edges under rather than over, which helps them stay in place and not tangle with hoses or feet.

Not much to see - spring broccoli under rowcover. Photo Kathryn Simmons — Not much to see – spring broccoli under rowcover.
Photo Kathryn Simmons

A week after transplanting, we’ll go through and replace any casualties with slightly younger plants. We’ll also put one plant of alyssum every 6ft down the center of each bed. After we remove the rowcover, this little flowering plant will attract beneficial insects like Braconid wasps, aphid parasites, and syrphid flies. These will deal with aphids and cabbage caterpillars. The paper wasps also carry off the cabbage caterpillars, so we rarely have serious caterpillar trouble.

Completing the broccoli planting means we now have 3 of our 10 row-crop plots planted out. Another one will be cover crops, so we have 6 left to go. Next up will be the Roma paste tomatoes and peppers, on biodegradable plastic. I need to sort out the drip tape for that this week.

Hoophouse in April - transition to summer squash from winter scallions and Bulls Blood beets. Photo Cass Russillo — Hoophouse in April – transition to summer squash from winter scallions and Bulls Blood beet greens.
Photo Cass Russillo

In the hoophouse we are making the transition from winter and spring crops to early summer crops. We have planted tomatoes, peppers and summer squash in the middles of the beds (gherkins to come soon), and we are hurrying up the harvesting of the winter crops which are competing for space and sunlight. We prefer to let the winter crops continue as late as possible, for maximum harvests. Soon we won’t need the hoophouse lettuce or greens as the outdoor senposai is ready to start harvesting and the lettuce heads are not far behind.

Watering seedlings in our greenhouse. Photo Pam Dawling — Watering seedlings in our greenhouse.
Photo Pam Dawling

We’ve moved a lot more flats out of the greenhouse to the coldfarmes to harden off for two weeks before we plant them out in the garden. Not everything goes to the coldframes – we keep the melons and celery inside so they don’t get too chilled, and the eggplant so they don’t encounter fleabeetles. the greenhouse work is starting to taper off for the season. One of the biggest occupiers of space are the flats of sweet potatoes – you can see the first two in the foreground of this picture. they are limp because they have only just been set in the flats. We’ll plant them out about May 10. You can read more about our method of growing sweet potato slips here and here. We’re well on track to have enough by the time it’s warm enough to plant out.

The weather here in central Virginia has been teasing us. It was hot, then cold again. We thought we were done with frosts, then we had some cold forecasts. We covered the strawberries for two nights to protect the flowers, and built height-extenders on the walls of the cold frames with plastic crates, so we could put the lids on without squashing the very tall plants we had in there. Then we got nights of 36F, 36F, 34F, 33F. We had covered the strawberries for the 36F nights, but not the 34F or the 33F, as we followed the forecasts too gullibly! Later today I’ll go to see if the strawberry flowers have black centers – the sure sign of a frost hitting the blossoms.

We always like to think we are done with frosts once we pass April 20, but the truth is our average last frost date for the past ten years is April 30, and the range has been 4/14 to 5/14, with a mean of 5/3.

A frosted strawberry flower with a black center. Photo Kathryn Simmons — A frosted strawberry flower with a black center.
Photo Kathryn Simmons