Introduction

Israel is a leading developer of greenhouse technology.  The primary impetuses for these innovations were a desire to help farmers to obtain larger crops than otherwise possible, and to allow for agricultural development in areas that were not considered arable.  It was later discovered that this method of growing could also bring great benefit to the kosher consumers because the conditions in the greenhouses could be manipulated to produce vegetables that were free of insects. 

However, our discussion will focus on another possible benefit of growing produce in a greenhouse, namely, are they possibly free of shemittah concerns?  There are two possible reasons why greenhouse produce should not be considered “shemittah produce”: (1) Such produce does not derive any nourishment from the ground and (2) Such produce is grown indoors.  In the coming paragraphs we will discuss these issues (known respectively as עציץ שאינו נקוב and זורע בבית ) and other possible reasons to be lenient.

This discussion is particularly relevant to those of us living out of Eretz Yisroel because greenhouse produce is exported to other countries, especially prior to Pesach, when many consumers look to buy bug-free romaine lettuce for use as marror at the Seder.  In many cases, such produce will be marked as being from a “מצע מנותק ” (disconnected bed) or from “חממות /greenhouses”.

עציץ שאינו נקוב

Plants that grow in flowerpots which have no holes in them (עציץ שאינו נקוב ), are mid’oraisah not considered to be growing in the “ground”, because the plants cannot draw nourishment from the ground.  As relates to most halachos, the halacha is quite clear that such plants are mid’rabannan considered to be attached to the ground.¹  However, Chazon Ish² points out that the Gemara never makes such a statement regarding Shemittah, and he suggests that possibly Chazal were especially lenient in this regard due to the hardship of observing Shemittah.  Although Chazon Ish’s conclusion is to be machmir on this issue,³ we will see that he considers it as a contributing factor towards being lenient in certain cases. 

Although greenhouse-grown produce might not always qualify as an עציץ שאינו נקוב due to details of which pots and plants qualify for that status,⁴ during the Shemittah year some companies line the floor of their greenhouses with thick plastic sheeting to guarantee that the plants are in fact considered to be growing in an עציץ שאינו נקוב .⁵  In modern Hebrew, produce which is grown in this manner is known as being from a “מצע מנותק ” (disconnected bed), and will often be labeled as such.

As an aside to this discussion it is worth noting that (a) most Poskim hold that the bracha on produce of an עציץ שאינו נקוב is shehakol⁶ but (b) such produce may be used for marror at the Seder.⁷ 

זורע בבית

Yerushalmi⁸ is unsure as to whether foods that grow in a house (זורע בבית ) are subject to the halachos of shemittah, and there is a debate in the Acharonim as to what the halacha is.  Rav Ovadiah Yosef⁹ accepts the ruling of Pas HaShulchan¹⁰ who is lenient, since the obligation of Shemittah nowadays is merely d’rabannan.  Others,¹¹ however, follow Chazon Ish¹² who takes a stricter approach regarding items grown in a house.¹³   Chazon Ish adds that he personally would assume that the same stringency should apply even if the pots are also an עצית שאינו נקוב but says that one should not protest those who are lenient in that case.  

At first glance, this discussion seems to exactly match the case of produce grown in a fully enclosed greenhouse (where the plants are also in an עציץ שאינו נקוב , as above), and such items should be free of Shemittah concerns according to the lenient opinions.  However, many contemporary Poskim argue with this comparison based on Chazon Ish’s analysis of the Yerushalmi.

Chazon Ish¹⁴reconciles Yerushalmi with Mishnah Shevi’is 2:4 by suggesting that Yerushalmi only considers that one may plant in a house during Shemittah when doing so is detrimental to the growth of the plants.  However, in cases where one covers or encloses a plant in a manner that protects and helps it, there is no question that such plants are included in all restrictions of Shemittah.  The Poskim take a few different approaches in relating this to the greenhouses used nowadays:

• Many say that although modern greenhouses are completely enclosed, their primary role is to facilitate better growth, and therefore they suggest based on Chazon Ish that even those who are lenient regarding זורע בבית (with or without עציץ שאינו נקוב ) would agree that produce of a modern greenhouse does not qualify for any leniency.¹⁵  Some of those who take this approach are willing to be lenient if there are other mitigating factors.
• Dayan Yisroel Yaakov Fisher¹⁶ agrees to the basic premise of this argument but contends that greenhouse produce is not as tasty as similar produce grown in the traditional manner.  Therefore he holds that one may plant in such an environment during Shemittah.
• Rav Moshe Sternbuch¹⁷ basically agrees with the strict approach but says that as relates to marror one should be lenient on the issue of greenhouse produce rather than eat “regular” romaine lettuce and take a chance of eating bugs (which would be an issur d’oraisah).

Other factors

There are a number of other possible reasons to be lenient regarding greenhouse produce during Shemittah, as follows:

Sale to a non-Jew

It has been suggested that the “flowerpots” and their contents can be sold to a non-Jew, and non-Jews can do all melachos d’oraisah for the plants.  Although on the surface this sounds very much like the well-known heter mechirah which many reject, the truth is that such a sale on flowerpots and greenhouses avoids the main issues that earlier Poskim had with the heter mechirah.  For this reason, Rav Elyashiv finds this arrangement acceptable if it is done in conjunction with עציץ שאינו נקוב and זורע בבית (as described above.¹⁸ Much of greenhouse produce sold during Shemittah with “Mehadrin” hechsherim, is certified based on this ruling.  Rav Vosner¹⁹ agrees to the halachic portion of this position, but argues that (a) exploiting this type of loophole on a grand scale is against the spirit of Shemittah and (b) doing so will lead people to erroneously believe that the general heter mechirah is acceptable.

Based on this line of reasoning any items produced in this manner would be considered to have been grown in a non-Jew’s land and would be subject to the controversy as to whether such foods are subject to kedushas shevi’is.  [The issue of kedushas shevi’is is beyond the scope of this document.]

Location of the greenhouses

The question of greenhouse produce of Shemittah was first addressed by Poskim in previous Shemittos when the bulk of this type of farming was done in Gush Katif.  This situation  presented an additional consideration as Gush Katif is located in an area that may be out of the halachic borders of Eretz Yisroel (as relates to Shemittah).  At the time, different Poskim weighed in as to whether this was a contributing factor.²⁰  Since then, the Israelis have chosen to abandon Gush Katif, and this issue has become moot.

Insect-free produce

As noted earlier, some Poskim who are otherwise strict on greenhouse produce during Shemittah, are inclined to be lenient as relates to the use of romaine lettuce for marror so as to help consumers avoid the issur d’oraisah of eating bugs.

Summary

We have seen that there are quite a number of reasons to permit greenhouse produce during Shemittah.  The following is a summary of the final conclusion of the contemporary sources we have cited, and are roughly listed in order of strictness (starting with the most lenient):

• Rav Yosef permits greenhouse produce in all cases since it grows indoors.
• Dayan Fisher is inclined to permit all greenhouse produce since it grows indoors, and says that if it is also an עציץ שאינו נקוב , then it is surely permitted.
• Rav Auerbach is lenient if the pots are also an עציץ שאינו נקוב .
• Rav Elyashiv is only lenient in the limited cases where the greenhouse is detrimental to the growth of the produce, the “pots” are an עציץ שאינו נקוב which is sold to non-Jews, and all melachos d’oraisah are performed by non-Jews. 
• Rav Vosner agrees with Rav Elyashiv on halachic grounds, but holds that it is improper to rely on this rationale on a large scale.
• Rav Shternbuch permits leafy vegetables from areas that may be outside of the halachic borders of Eretz Yisroel (e.g. Gush Katif) if it is not possible to purchase bug-free produce from non-Jews.  [It is not clear whether he would be lenient nowadays when the produce no longer comes from Gush Katif.]
• Dayan Weiss appears to hold that it is improper to use greenhouse produce under any circumstances.