“No,” replied her father, “it doesn’t.  If celery were left to grow as it comes up from seed the stalks would be green, or at least only the hearts, or the most inside part, would be white.

“To make celery white all over we have to keep the sun from shining on it.  For it is the rays of the sun, together with the juices, or sap, inside leaves and plants, that makes them green.  Celery has to be bleached, and one way of doing it is to set long boards on each side of the row of celery plants, fastening them close up, and covering them with straw and dirt to keep out all the light.

“Some farmers bank up the dirt on both sides of their plants, not using any boards, but I like the boards because they are clean, and keep the soil from getting inside the celery stalks.  Another way is to put a small wooden tube, or barrel around each plant so that no sunlight can get to the sides of the stalk to make them green.”

“Isn’t it queer,” said Mab.  “I thought celery always grew white, like we get it at the table.  And so it has to be bleached.  If you keep the light from anything green will it turn white, Daddy?”

“Well, almost anything, like plants.  Children turn pale if they do not get enough sunlight and so does celery.  Only we like pale celery but it is not healthful for children to be too white.  Just try a little experiment yourself.  Take a flat stone and put it over some grass.  In a week or so lift up the stone and see what has happened.”

Hal and Mab did this, after they had helped their father put the boards on the celery.  Then, a week later, they lifted up the stone which they had laid over a spot on the lawn.

“Why, the green grass has all turned white!” cried Hal.  And so it had.

“That’s how my celery will turn,” said his father.  “The grass grew pale from being in the dark so long.  It did not like it, and if you left the stone there too long the grass would die.  Now take it away and in a day or so the grass will be green again.”

And that’s exactly what happened.  The sun had tanned the grass green as it tans children brown at the seashore.

One day, when Mab and Hal had started out with their father who was going to show them how to dig potatoes, which is not as easy as it sounds, the children suddenly heard a yelping and barking sound in Mr. Porter’s garden.

“There’s Roly-Poly in trouble again!” called Mr. Blake.

“Yes, and he’s hurt, too!” added Hal, for the little poodle was yelping as if in pain.

“Oh, what has happened to him?” cried Mab.  “Hurry, Daddy, please, and see!”

CHAPTER XI

GATHERING CROPS

Hal, Mab and their father ran to the gate in the fence that was between their yard and the garden of Mr. Porter.  Down where their neighbor’s lima beans were planted, and where they were climbing up the poles, they heard the barking and yelping of Roly-Poly sounding loudly.