Growing squash – problems and solutions
Squash plants love the hot summer sun, and Kansas has plenty of it! Any vegetable gardener in the state who has been growing for very long will likely have planted some variety of squash. There are a few issues that can pop up when growing squash, but overall, it is usually pretty easy to grow.
In the Demo garden, we are growing both summer squash and winter squash. Contrary to what the names imply, both types of squash are grown during the heat of summer; one main difference is that summer squash is grown for its young or immature fruit (think zucchini), while winter squash is grown for its fully mature fruit, so it takes longer to be ready (think butternut squash or pumpkins).
Summer squash grows in a bushy shape and is generally ready to harvest by mid-summer. When harvested at small sizes, they have a soft, thin skin and unsubstantial seeds and can be eaten raw. If left on the plant to grow very large, though, they become tough and too bitter to eat raw. The most popular types of summer squash are zucchini and yellow squash, but other types include pattypan and tromboncino.
We have two varieties of summer squash in the demo garden, and both are varieties of zucchini: ‘49er’ and ‘Astia,’ which both are beginning to yield a harvest.
‘49er’ is a yellow zucchini which has about 50 days to maturity (DTM), and ‘Astia’ is a dark green zucchini with 48 DTM. Both are best harvested at about 5-6 inches long. (Yellow squash and yellow varieties of zucchini are similar, but different; zucchini maintains a relatively consistent diameter, whereas yellow squash is broader at one end and tapers toward the other, and often has a slightly thicker skin than zucchini.)
Winter squash generally has a vining nature and needs either lots of space to sprawl out or a trellis to grow vertically when space is at a premium. Because it is harvested when fully mature, it has a tougher skin than summer squash that is not usually eaten. Winter squash is usually ready to harvest late summer or early fall. One of the benefits of growing winter squash is that it can store well, even through the winter months. The winter squash in the demo garden (‘Waltham’ butternut and ‘Autumn Frost’ acorn squash varieties) are setting fruit but won’t be ready to harvest for several more weeks. We’ll keep you posted!
A couple of the biggest challenges with growing squash are the squash vine borer and the squash bug. Both of these insects can wreak significant havoc and are taking their toll now in the Demo garden.
The classic symptom of squash vine borer is a wilted plant when the plant has been watered well and shouldn’t be drooping. Upon closer inspection, you may be able to see that the stem has small holes or is chewed up close to the ground with larvae frass at the base. At this point, it is important to remove the larvae by either disposing of the plant completely, or, if you’re feeling surgical, slitting the vine with a sharp knife until you find the larvae and then removing it. The slit vine can be placed back in the soil and kept moist in the hopes that it will send off new roots, but some plants may have been damaged beyond repair and won’t recover from the “surgery.” If the larvae are not removed and are allowed to complete their life cycles in your garden (in which they eat their way out of the stem, burrow 1-2 inches into the soil, and wait in a cocoon until the next season), the problem will likely return next year. Once you have squash vine borers, there is not a whole lot you can do; to learn about treatment options and cultural controls, see this helpful publication.
Another pest we are facing in the Demo garden is squash bugs. Adults look similar to stink bugs and can be found on many species of the cucurbit family, but squash is their favorite. Adults and nymphs (which are lighter grey with black legs) cause damage by sucking out juices from plant leaves, resulting in yellowing, wilting, and death of the plant when populations are large. Squash bug eggs can be found by scouting on the under sides of leaves – they are glossy brown and laid in groups in between leaf veins. These eggs can be scraped off and disposed of to help control, but here in the Demo garden, the problem has passed the egg stage, and we have begun chemical control to limit the damage. Squash bugs are best controlled at the nymph stage, since adults have a hard shell that protects them from pesticides. We have applied one round of spinosad by spraying it on the vine and branches where the nymphs are congregating. We won’t be able to harvest zucchini for at least three days after spraying, and depending on what the squash bug population looks like after the application, we may spray again in about a week. We use chemicals sparingly in the Demo garden, which are safe when used appropriately. As always… when using chemical pesticides, make sure read and follow the label! To learn more about squash bugs, click here.
One last issue we had with the zucchini earlier this year was small fruit (around 3 inches) that shriveled up or rotted from the blossom end of the fruit before coming to harvestable size. This symptom can be due to a couple of different culprits, but is ultimately related to an issue with pollination.
Sometimes high temperatures following a mild or cool spell can limit the number of pollinators that are active in the garden; sometimes over-fertilization (high nitrogen levels) in the soil can cause the plant to produce too many male flowers; and sometimes plants don’t produce enough male and female flowers at the same time to ensure enough pollination (this issue usually resolves itself as the season progresses.)
We stepped in to lend our zucchini plants a pollinating hand, and you can too if you see this issue in your garden – it is as simple as taking the pollen from the male flowers and transferring it to the female flowers. First, identify which flowers are female and which are male; female flowers often have a swelling behind the flower head where the fruit is barely beginning to form, whereas male flowers have a straight stem behind the flower head. Another, perhaps more reliable way to tell is to look inside the flower: the female has a stigma which is larger and slightly round or bulbous, and the male has a single, straight appendage – the anther – inside the flower.
Hand-pollinating can easily be done by using a small artist-sized paint brush to transfer pollen from the male to the female flowers; lightly touch the tip of the brush to the anther on a male flower and dab the pollen that the brush picked up onto the stigma of a female flower.
With a couple hand-pollinating sessions, a relative evening-out of temperature, and an uptick in pollinators in the garden, our zucchini are now producing harvestable fruit. Now it’s a matter of fending off the squash bugs so that we can keep harvesting this delicious summer garden staple!
Resources for further reading:
By: Maureen Wilbeck, Master Gardener
A Look at the Parthenocarpic Squash
Outwitting the squash vine borers is one of the ongoing themes in the garden this summer. Let’s take a look at our parthenocarpic (no pollination needed) squash trial.
This is the fancy cage we built for the row cover over the squash. We hadn’t really made new row covers/low tunnel frames for the new raised beds yet, so this seemed like a good opportunity to try something new. One of the things that I’ve always struggled with on our raised beds is how to manage the lower edges without resorting to a bunch of bricks or milk jugs of water. I had this idea to use a PVC frame along the bottom edge that the row cover could be clamped to. We also decided to make a larger, square frame because the squash get big, especially under cover.
The biggest problem we’ve had is that there’s no good way to open the row cover when we need to get in and work on the plants or harvest. When we take the clamps off, it tends to tear the fabric. So…it’s a good idea, but still a work in progress.
That’s what the clamps look like, in case you were curious.
The squash under the row cover are looking quite jungle-esque. This is pretty typical when you have plants under a row cover. They are protected from the wind and they are slightly shaded, so they tend to get a little bit tall and leggy. You can see the longer, skinnier stems on these plants compared to what you might expect. It’s also nice and warm under the row cover, so the plants grow quickly.
As you can see, we are starting to get some flowers. With most squash, when using row cover to circumvent the squash vine borer, we would take the row cover off right now. However, since we are using parthenocarpic varieties that supposedly require no pollination to set fruit, we shouldn’t need to do that. It will allow the protection to continue until we take the row covers off.
So…is that translating into squash? As you can see from this picture, the answer is not so much. There are several squash that are clearly rotting and have not successfully set. Now, it could just be early and this will straighten out. It could be that the varieties we picked are only partially parthenocarpic. Or it could be that the project is a big bust and we’ll have to take the row cover off to get any zucchini. I looked up the varieties we chose to see if there was any data on how they do. ‘Partenon’ was listed as setting fruit 69% of the time parthenocarpically. I didn’t find any data on ‘Segev’. So, we’ll see how things continue! The plus side is that even if we have to take off the row cover now, the plants should be large enough to withstand quite a bit of squash vine borer damage before they die.
Family of 4 Garden Harvest Report
Today was an exciting day in the Family of 4 Garden! We actually had some tomatoes to harvest! They turned out to be not beautiful – one with a crack and one with a touch of blossom end rot (shock!). But they were still tomatoes. The cucumbers and zucchini are still producing quite well, although we ended up pulling out the zucchini due to powdery mildew. The cucumbers are slowing down quite a bit, probably because they are coated in aphids. I’ll post more about these two occurrences tomorrow or Thursday.
4.5 lbs of cucumbers @ $1.00/lb = $4.50
2.25 lbs of zucchini @ $1.50/lb = $3.38
0.56 lbs of tomatoes @ $2.00/lb = $1.12
Weekly Total = $9.00
Year to Date = $115.05
Family of 4 Harvest Update
Yesterday was just a zoo here at the Demo Garden (and in the office!), so I didn’t have a chance to update you on our Family of 4 garden harvests.
Let’s just say that the ‘Homemade Pickles’ cucumbers are not lagging anymore! They weighed in at 12.5 lbs yesterday, and I could probably find more today if I wanted to dig around in the cucumber vines. Ugh.
Cucumbers = 12.5 lbs @ $1.00/lb = $12.50
Zucchini (green & gold) = 20.25 lbs @ $1.50/lb = $30.38
Weekly Total = $42.88
Year to Date = $54.01
(Just in the interest of full disclosure, I did add $10 beyond what I’ve already reported this year, just because we’ve had a couple weeks of zucchini and a few cucumbers that didn’t get added in the way they should have.)
Just for fun, I looked back to see where we were at in previous years in the Family of 4 Garden.
July 20, 2010 – $163.86
July 19, 2011 – $163.39
Given last summer being so atrocious, it’s kind of surprising that there was only 47 cents difference between the two years at this point. Of course, in both years we had a lot of spring vegetables. Last year, after recording $163.39 on July 19th, we didn’t break $170 until September 6th! In 2010, we were over $215 by that point.
This year, our expectations are going to have to be different. First of all, we planted in mid-May, losing all opportunity for spring vegetables. Second, our Family of 4 Garden is only about 4′ x 14′, as opposed to the 4′ x 25′ that we have had in the past. Then, with the beans and tomatoes affected by some herbicide damage, we had to pull the beans and the tomatoes are not very strong. At this point, we are pretty much going to be running with cucumbers and zucchini for the year! We’ll get some fall things planted in another month, hopefully, but it may be a challenge to get to $150 this year.
Garden Plans for 2012: Mexican Garden
Another one of our theme gardens this year is the Mexican Garden. This garden is going to be a fun mix of more commonly recognized vegetables with some uncommon vegetables!
We relied heavily on Rosalind Creasy’s book, The Edible Mexican Garden, for inspiration in planning our Mexican Garden.
Starting from the left side, we of course had to put in several peppers. Since we had so many peppers last year, we didn’t want to go crazy. Still, we have 6 peppers, ranging from serrano to bell peppers. Then we have a few rows of a black bean that can be used as either a dry bean or a fresh shelling bean. With the amount of space allotted, we know that we won’t get tons of beans, but it should be enough to have fun growing them.
Of course, the herb most people associate with Mexican cooking is cilantro, because it is in salsa. Unfortunately, cilantro doesn’t like the heat here very much in the summer, so we are also growing culantro. Culantro is an herb that has a similar flavor to cilantro but much better heat tolerance. We’ll also have a Mexican Oregano plant.
Cantaloupe are also a native Mexican vegetable/fruit! We are reprising the ‘Tasty Bites’ melon from last year on a trellis, as well as giving a shot at growing jicama. Jicama is a tuber vegetable, but the plant is a huge vine. It needs a long growing season, so it will be fun to see if we get anything from it.
You might have noticed that we skipped the tomatoes in the Mexican Garden, in favor of 4 tomatillo plants. Supposedly tomatillos produce better if they have another tomatillo as a pollinator, so we decided to try a purple tomatillo (2 plants) and an large green tomatillo (2 plants).
The two zucchinis are a paler grey color, rather than a typical green or yellow on a summer squash. The ‘Ronde de Nice’ is actually a round zucchini.
All the way on the right side of the map, we have 2 plants of ‘Aztec Red’ Spinach. Don’t let the name fool you – this is not a spinach in the sense we normally use it. It is a native Mexican green called Huauzontle (or Huauzontli). It is in the same family as Lambs’ Quarter, a common weed, which is also edible. The young, tender leaves of the huauzontle are eaten, as well as the immature flower buds. This will be a fun one to experiment with on some recipes this summer!