2011 Squash Patch

It's been a while since I've written anything about my squash patch, but there are some topics that I want to cover this season. I've cut back on my market gardening efforts this year, but I did plant a significant squash patch on June 26. That's about my usual time for planting squash. I wait to see squash bugs before planting. When the bugs don't find any squash growing in my garden they leave and go elsewhere. The late-growing squash are generally not bothered by squash bugs.

This season may be different. Cold and rainy weather delayed growth and development of both crops and pests by about 3 weeks, maybe more. I didn't want to wait for the bugs for much beyond end of June, or there will not be time for fruit to develop. We'll see if planting late means avoiding bugs this year.
So, here's my squash patch as it looked on June 27, looking south toward our house and small young orchard. There are 60 squash hills, each with about 3 seeds planted. As in previous years, there are lots of squash varieties, including three types of patty pan shapes , three round zucchini, two middle-eastern varieties, and about 6 regular zucchini varieties, all in dark green, light green and yellow varieties. In addition, I have seed from the F1 generation of a mutant plant that grew in 2008. I saved the seed, and planted some in 2009 and more in 20010. I had some interesting shapes that I called minaret, green papaya pear, and avocado. This year I planted some of the 2009 seed again (I did not get any fruit in 2010). So I want to document my simple efforts at plant breeding and seed saving this season. New shapes will be a nice addition to the squash that I sell.

Temperatures had warmed enough by early July for quick seedlings emergence. Here's one of the first hills to have cotyledons emerging, on July 4.


This photo shows the seedlings for one of the more advanced hills as of July 15, the day after an irrigation. There are three or four leaves beyond the cotyledons at this point for many of the hills. The seeds are slower to germinate in some hills. A few hills had to be replanted.

Here's the squash patch on July 15. Look close and you'll see the young squash seedlings. There are also quite a few weeds. The tallest "weeds" are alfalfa plants. I'm going to try to keep them in the garden so that when the season is over, the alfalfa will still be around to serve as a cover crop next year.

Continued Seedling Growth

This morning I counted 51 hills of the 58 with at least one set of cotyledons up. Some seem to be taking their time coming up. In some cases the first true leaf is up, and even the second leaf. The top photo is a hill of a zucchini type of squash, with the first true leaf coming to a point. The bottom photo is a patty-pan type of squash, with a more rounded first leaf. The zucchini leaves also have some whitish patches that are lacking in the patty pans, but they are hard to see in this image.

In a few weeks there will be squash for sale at the Nampa Farmers' Market!

I've done a little work in the squash bed since planting the seeds. First, I scattered sulfur pellets and rock phosphate pellets on each hill. I should have scattered them around the garden when we put the compost on, but I forgot, or didn't have time. It's OK to get them on late. The sulfur dissolves with irrigation into sulfuric acid which temporarily decreases the soil pH. Our soil is very alkaline, about 8.3. By adding sulfur, I can lower the pH for a while to something closer to a neutral 7.0 which is most plants prefer over the high 8.3 alkaline soil. It's a temporary fix; I'll have to add sulfur again once or twice this season to keep the pH low.
The lower pH also helps make iron more readily available to the plant. Iron binds with soil particles at high pH, preventing the plant from using it. The leaves start to yellow. Lower the pH and the plant can absorb more iron, and they leaves are a richer green color.

Phosphorus is not a problem in our soil generally, but I like to add a little to crops that have fruits. Once tomatoes, eggplants, peppers and squash start to flower and set fruit, they use more phosphorus. You don't want to give the plants too much nitrogen or they get very leafy and don't produce as many fruit.

I've also spread some straw over the ground around some of the squash hills to help keep in moisture. This may help bring up the seedlings that have been slow to sprout. I need to spread more straw this weekend. The straw may also hold down weeds some, but the weeds seem to grow through anyways. So, my main reason for the straw mulch is to conserve soil moisture.

Time spent so far on the squash patch:
20 minutes spreading sulfur and phosphorus
20 minutes spreading straw
15 minutes planting three additional hills, and replanting 3 hills with no seedlings yet.
Total so far: ~10.5 man hours

What's happening down there?

We planted on Tuesday, and now it's Sunday, 5 days later. True to the seed packets, when I went out to check my garden this morning, there were squash cotyledons emerging from about 14 of my 58 squash hills. Good start!

So, for 5 days, the soil appeared barren, and then all of a sudden these fleshy green leaves have emerged. What's been happening down there under the soil?

I don't know much about seed physiology, but I googled the topic and found the first page of a 1956 review of the topic. While I'm sure that much has been learned since then, the authors describe the basic process very well. They write "A seed contains an embryonic plant in an inactive condition, and germination is the resumption of growth." Right there is a bit of a surprise. A resumption of growth. Because the growth started while the seed was forming in the fertilized ovary - part of the original flower.

"The young plant, protected by varying layers of living and dead tissue, has reserves for metabolism. In some seeds development takes place as soon as water is absorbed, but in others germination does not take place until additional requirements are met." Squash seeds are large, so they have lots of reserves for metabolism. They are the type of seeds that start to develop as soon as water is absorbed. They don't require scarification or cold treatment, for example.

"Three distinct stages are evident in germinating seeds, namely (a) imbibition of water, (b) cell elongation, and (c) increase in cell number. In a physiological sense, the start of germination depends on a coupling of respiration to growth. The established seedling results from resumption of development and its continuation through growth." So my seeds have been taking up water, increasing the size of their dried up cells, and multiplying their cells.

That's as far as I could read the article without a subscription to Annual Review of Plant Physiology.

A bulletin from Washington State University explains a little more: "The first sign of germination is the absorption of water -- lots of water. This activates an enzyme, respiration increases and plant cells are duplicated. Soon the embryo becomes too large, the seed coat bursts open and the growing plant emerges. The tip of the root is the first thing to emerge and it's first for good reason. It will anchor the seed in place, and allow the embryo to absorb water and nutrients from the surrounding soil."

So, tomorrow we'll give them some more water, and the rest of the seedlings should be up in a few days, respiring, photosynthesizing, and multiplying their cells into a young seedling.