Halacha

הלכה א
זֶרַע שֶׁנִּתְעָרֵב בּוֹ זֶרַע אַחֵר אִם הָיוּ אֶחָד מֵעֶשְׂרִים וְאַרְבָּעָה כְּגוֹן סְאָה שֶׁל חִטִּים שֶׁנִּתְעָרְבָה בְּעֶשְׂרִים וְשָׁלֹשׁ סְאָה שֶׁל שְׂעוֹרִים הֲרֵי זֶה אָסוּר לִזְרֹעַ אֶת הַמְעֹרָב עַד שֶׁיְּמַעֵט אֶת הַחִטִּין אוֹ יוֹסִיף עַל הַשְּׂעוֹרִים וְאִם זָרַע לוֹקֶה:
כסף משנה
1.
[The following rules apply when] seeds [of one species] are mixed together1As stated in Halachah 6, this and the following halachot apply when the mixture came about unintentionally. If the mixture was made intentionally, even the slightest amount is forbidden. with seed of another [species]. If the smaller quantity was one twenty-fourth [or more of the entire mixture], e.g., a se'ah of wheat became mixed with 23 se'ah of barley,2When quoting this law, the Shulchan Aruch (Yoreh De'ah 297:5) speaks of 24 se'ah of barley. it is forbidden to sow the mixture unless one reduces the amount of wheat3By removing the kernels. or adds to the amount of barley.4So that the amount of wheat will no longer be considered significant.
The Jerusalem Talmud (Kilayim 2:1) refers to the general principle (Beitzah 4b) that we do not nullify the existence of a prohibited substance. Why then are we allowed to add more barley and thus nullify the presence of the wheat?
It explains that the mixture is forbidden only because of the appearance created, i.e., as stated in Chapter 3, Halachah 5, mixed substances are forbidden only if the mixture is noticeable to the eye. Hence, if the barley is added before the mixture is sown, when the crops grow, the mixture will not be noticeable. Hence, there is no prohibition involved (Rambam LeAm).
If he sowed [the mixture as is], he is liable for lashes.5There are those who interpret the Jerusalem Talmud as implying that in this instance, the prohibition is merely Rabbinic in origin. Hence, they question this ruling. According to the explanation in the previous note, however, there is no difficulty.

הלכה ב
וְכָל שֶׁהוּא כִּלְאַיִם עִם הַזֶּרַע מִצְטָרֵף לְאֶחָד מֵעֶשְׂרִים וְאַרְבַּע. כֵּיצַד. עֶשְׂרִים וְשָׁלֹשׁ סְאָה שֶׁל חִטִּים שֶׁנִּתְעָרֵב בָּהּ שְׁנֵי קַבִּין שְׂעוֹרִים וּשְׁנֵי קַבִּין עֲדָשִׁים וּשְׁנֵי קַבִּין פּוֹלִים הֲרֵי זֶה לֹא יִזְרַע הַכּל עַד שֶׁיְּמַעֵט סְאָה שֶׁל תַּעֲרֹבֶת וְיָבֹר מִקְצָתָהּ אוֹ יוֹסִיף עַל הַחִטִּים. שֶׁהַשְּׂעוֹרִים וְהָעֲדָשִׁים וְהַפּוֹל כֻּלָּם כִּלְאַיִם עִם הַחִטִּים:
כסף משנה
2.
Any [species of seed] that is considered a forbidden substance with the seeds [that are mixed in] is included in the sum of one twenty-fourth. What is implied? 23 se'ah of wheat were mixed together with two kabbin of barley, two kabbin of lentils, and two kabbin of beans.6There are six kab in a se'ah. Thus there is not enough of any one different species for it to be considered as a forbidden mixture on its own. Nevertheless, since when combined, there is a significant amount of seeds of other species, the mixture is forbidden. He should not sow the entire mixture until he reduces the se'ah of mixed substances by removing part of it or adding to the wheat, for barley, lentils, and beans are all considered as kilayim with wheat.

הלכה ג
בַּמֶּה דְּבָרִים אֲמוּרִים בְּשֶׁנִּתְעָרְבוּ מִינֵי תְּבוּאָה זֶה בָּזֶה אוֹ מִינֵי קִטְנִיּוֹת זֶה בָּזֶה אוֹ שֶׁנִּתְעָרְבָה תְּבוּאָה בְּקִטְנִיּוֹת אוֹ קִטְנִיּוֹת בִּתְבוּאָה. אֲבָל זֵרְעוֹנֵי גִּנָּה שֶׁנִּתְעָרֵב אֶחָד מֵהֶן בִּתְבוּאָה אוֹ בְּקִטְנִיּוֹת שִׁעוּרָן אֶחָד מֵעֶשְׂרִים וְאַרְבָּעָה מִמַּה שֶּׁזּוֹרְעִין בְּבֵית סְאָה מֵאוֹתוֹ הַמִּין אִם נִתְעָרֵב בִּסְאָה שֶׁל תְּבוּאָה אוֹ קִטְנִית לֹא יִזְרַע עַד שֶׁיְּמַעֵט אוֹ יוֹסִיף עַל הַתְּבוּאָה:
כסף משנה
3.
When does the above apply? When the different types of grain are mixed together, the different legumes are mixed together or grain is mixed with legumes or legumes mixed with grain. If, however, species of garden seeds are mixed with grain or beans, the measure [which is considered significant] is one twenty-fourth of what would be sown of that species7The seeds of garden vegetables are far smaller than those of grains and legumes. Thus a far lesser amount is necessary to produce a crop. We must take this factor into consideration in these calculations [Rav Ovadiah of Bartenura (Kilayim 2:2)]. in the area necessary to sow a se'ah [of grain].8I.e., a square 50 cubits by 50 cubits, or any area of 2500 sq. cubits. If [this amount] is mixed with a se'ah9According to the Rambam's statement in Halachah 1, the intent is not a se'ah, but one-twenty-fourth less. of grain or legumes, one should not sow the mixture unless he reduces [the garden seeds] or adds to the grain.

הלכה ד
כֵּיצַד. חַרְדָּל שֶׁנִּתְעָרֵב בִּתְבוּאָה וַהֲרֵי הַחַרְדָּל זוֹרְעִין מִמֶּנּוּ קַב בְּכָל בֵּית סְאָה אִם נִתְעָרֵב מִמֶּנּוּ אֶחָד מֵעֶשְׂרִים וְאַרְבָּעָה מִן הַקַּב בִּסְאָה שֶׁל תְּבוּאָה אוֹ שֶׁל קִטְנִית חַיָּב לְמַעֵט. וְכֵן אִם הָיָה מִין זֶה מִזֵּרְעוֹנֵי גִּנָּה זוֹרְעִין מִמֶּנּוּ סָאתַיִם בְּכָל בֵּית סְאָה אִם נִתְעָרֵב מִמֶּנּוּ חֲצִי קַב בְּכָל סְאָה שֶׁל תְּבוּאָה אוֹ שֶׁל קִטְנִית יְמַעֵט:
כסף משנה
4.
What is implied? [For example,] mustard seed was mixed with grain. Now a kav10One sixth of a se'ah. of mustard seed is sown in the area fit for a se'ah of grain. If one twenty-fourth of a kav of mustard seed is mixed with a se'ah11I.e., a square 50 cubits by 50 cubits, or any area of 2500 sq. cubits. of grain or legumes, one must reduce [the mustard seed]. Similarly, if it was customary to sow two se'ah of a species of garden seeds in an area where a se'ah of grain would ordinarily be sown,12I.e., we are speaking about sowing seeds that are bulkier than the seeds of grain and a larger amount is necessary to be sown in the area in which a se'ah of grain seeds would be sown. should a half a kav13I.e., one twenty-fourth of two se'ah, double the ordinary amount. be mixed in a se'ah of grain or legumes, it must be reduced.

הלכה ה
לְפִיכָךְ תְּבוּאָה שֶׁנִּתְעָרֵב בָּהּ זֶרַע פִּשְׁתָּן אִם הָיָה שְׁלֹשֶׁת רְבִיעִים בְּכָל סְאָה הֲרֵי זֶה יְמַעֵט. וְאִם לָאו אֵינוֹ צָרִיךְ לְמַעֵט. לְפִי שֶׁבֵּית סְאָה זוֹרְעִין בּוֹ שָׁלֹשׁ סְאִים זֶרַע פִּשְׁתָּן. וְעַל דֶּרֶךְ זֶה מְשַׁעֲרִים בְּכָל הַזְּרָעִים הָאֲחֵרִים:
כסף משנה
5.
Therefore, [the following laws apply if] grain becomes mixed with flax seed. If there were three quarters [of a kav] in every se'ah [of grain], it is necessary to reduce the amount [of flax]. If there is less than that [amount], it is not necessary to make such a reduction. [The rationale is that] in an area fit to sow a se'ah [of grain], it is customary to sow three se'ah of flax seeds. This pattern is followed with regard to all other types of seeds.

הלכה ו
בַּמֶּה דְּבָרִים אֲמוּרִים בְּשֶׁלֹּא נִתְכַּוֵּן לְעָרֵב וּבְשֶׁלֹּא נִתְכַּוֵּן לִזְרֹעַ הַשְּׁנֵי מִינִין שֶׁנִּתְעָרְבוּ. אֲבָל אִם נִתְכַּוֵּן לְעָרֵב זֶרַע בְּזֶרַע אַחֵר אוֹ לִזְרֹעַ הַשְּׁנֵי מִינִין אֲפִלּוּ הָיְתָה חִטָּה אַחַת בְּתוֹךְ כְּרִי שֶׁל שְׂעוֹרִים אֲסוּרָה לְזָרְעָהּ. וְכֵן כָּל כַּיּוֹצֵא בָּזֶה:
כסף משנה
6.
When does the above apply? When one did not intend to mix the two species and one did not intend to sow a mixture of the two species. If, however, one intended to mix one species of seed with another species or to sow two species,14I.e., after the two species were mixed together accidentally, the person sowed the mixture with the intent of benefiting from both species (Kessef Mishneh). it is forbidden to sow even one kernel of wheat with an entire grainheap of barley. Similar laws apply in all analogous situations.

הלכה ז
הַזּוֹרֵעַ שָׂדֵהוּ מִין מִן הַמִּינִין וּכְשֶׁיִּצְמַח רָאָה בּוֹ כִּלְאַיִם. אִם הָיָה הַמִּין הָאֶחָד אֶחָד מֵעֶשְׂרִים וְאַרְבָּעָה בַּשָּׂדֶה הֲרֵי זֶה יִלְקֹט עַד שֶׁיְּמַעֲטֶנּוּ מִפְּנֵי מַרְאִית הָעַיִן. שֶׁמָּא יֹאמְרוּ כִּלְאַיִם זָרַע בְּכַוָּנָה. בֵּין שֶׁהָיָה הַמִּין הָאֶחָד שֶׁצָּמַח תְּבוּאָה וְקִטְנִית בִּתְבוּאָה וְקִטְנִית. אוֹ זֵרְעוֹנֵי גִּנָּה בִּתְבוּאָה וְקִטְנִית וּבְזֵרְעוֹנֵי גִּנָּה. וְאִם הָיָה הַצּוֹמֵחַ פָּחוֹת מִיכַּן אֵינוֹ צָרִיךְ לְמַעֲטוֹ:
כסף משנה
7.
[The following rules apply when] a person sowed a particular species in his field,15I.e., with the intent that each one grow in a separate place. but when the crops grow, he saw that there are intermingled species there.16And he does not desire to benefit from the intermingled species (Turei Zahav 297:3). If the [intermingled] species covered one twenty-fourth of the area in the field, he should gather it until he reduces the amount because of the impression that might be created.17In the initial halachot of this chapter, a Scriptural prohibition was involved, as evident from the fact that the person was punished by lashes. For those halachot were speaking about instances where the person desired to benefit from the forbidden mixture. In this instance, we are speaking about an instance where he did not desire to benefit. Hence there is only a Rabbinic prohibition involved (Turei Zahav 297:4). Alternatively, the explanation given in note 3 can be employed here as well. [An onlooker might think that] perhaps he sowed mixed substances intentionally. [This applies] whether the [intermingled] species that grew was grain and legumes amid grain and legumes or garden seeds amid grain, legumes, and garden seed. If the amount that grew was less than this, he does not need to reduce it.

הלכה ח
בַּמֶּה דְּבָרִים אֲמוּרִים בִּזְמַן שֶׁיֵּשׁ מָקוֹם לַחֲשָׁד. אֲבָל בִּזְמַן שֶׁהַדְּבָרִים מַרְאִין שֶׁאֵין זֶה מִדַּעְתּוֹ שֶׁל בַּעַל הַשָּׂדֶה אֶלָּא מֵאֲלֵיהֶן עָלוּ אֵין מְחַיְּבִין אוֹתוֹ לְמַעֵט:
כסף משנה
8.
When does the above apply? When there is a reason to suspect [that he did so intentionally]. When, however, it is apparent from the situation that this was not the owner's intent, but the [intermingled species] grew on their own accord, we do not require him to reduce their amount.

הלכה ט
כֵּיצַד. כְּגוֹן תְּבוּאָה שֶׁעָלוּ בָּהּ סְפִיחֵי אִסְטִיס וְתִלְתָּן שֶׁזְּרָעָהּ לְמַאֲכַל אָדָם שֶׁעָלוּ בָּהּ מִינֵי עֲשָׂבִים שֶׁזֶּה מַפְסִיד הוּא. וְכֵן כָּל כַּיּוֹצֵא בָּזֶה:
כסף משנה
9.
What is implied? Indigo grew in [a field of] wheat. Grass grew in [a field of] chilbah18A pungent herb also known as fenugreek. planted for human consumption.19Instead of for animal fodder, as is also done on occasion. [It is obviously undesirable, because the intermingled species] damage the primary species. Similar laws apply in all analogous situations.

הלכה י
וּבְמַה יִּוָּדַע שֶׁהַתִּלְתָּן זְרוּעָה לְמַאֲכַל אָדָם. כְּשֶׁהָיְתָה זְרוּעָה עֲרוּגוֹת עֲרוּגוֹת וְלָהּ גְּבוּל סָבִיב. וְכֵן מְקוֹם הַגֳּרָנוֹת שֶׁעָלוּ בָּהּ מִינִין הַרְבֵּה אֵין מְחַיְּבִין אוֹתוֹ לַעֲקֹר. שֶׁהֲרֵי הַדָּבָר יָדוּעַ שֶׁאֵינוֹ רוֹצֶה שֶּׁיִּצְמַח צֶמַח בִּמְקוֹם הַגֳּרָנוֹת. וְאִם הֵסִיר מִקְצָתָן אוֹמְרִין לוֹ עֲקֹר הַכּל חוּץ מִמִּין אֶחָד שֶׁהֲרֵי גִּלָּה דַּעְתּוֹ שֶׁרוֹצֶה בְּקִיּוּם הַשְּׁאָר:
כסף משנה
10.
How is it possible to know whether the chilbah is planted for human consumption? When it is sown in a series of rows and there is a border around it.20And not in a haphazard manner [the Rambam's Commentary to the Mishnah (Kilayim 2:5) based on Bava Kama 81a].
Similarly, if different species grew in the place of the grainheap, we do not require him to uproot them, for it is known that he does not desire plants to grow in the place of the grainheap.21That place has to be flat and smooth so that the grain can be threshed (ibid.). If he removed some of the growths - which indicates that he desires to maintain [the plants] that remain - we tell him to uproot everything except one species.22For anything more than one species would be considered kilayim.

הלכה יא
אֵין נוֹטְעִין יְרָקוֹת בְּתוֹךְ סַדָּן שֶׁל שִׁקְמָה וְכַיּוֹצֵא בָּהּ. הַטּוֹמֵן אֲגֻדַּת לֶפֶת וּצְנוֹן וְכַיּוֹצֵא בָּהּ תַּחַת הָאִילָן אֲפִלּוּ תַּחַת הַגֶּפֶן. אִם הָיוּ מִקְצָת הֶעָלִין מְגֻלִּין אֵינוֹ חוֹשֵׁשׁ שֶׁהֲרֵי אֵינוֹ רוֹצֶה בְּהַשְׁרָשָׁתָן וְאִם אֵינָן אֲגֻדָּה אוֹ שֶׁלֹּא הָיוּ הֶעָלִין מְגֻלִּין חוֹשֵׁשׁ מִשּׁוּם כִּלְאַיִם:
כסף משנה
11.
We may not plant vegetables in a stump of a wild fig tree or the like.23I.e., grafting vegetables onto any other tree is also forbidden, as stated in Chapter 1, Halachah 5.
The Radbaz states by using the term "wild fig tree," instead of fig tree, the Rambam - and his source, Kilayim 1:9 - are emphasizing that even though one might think that a wild fig tree resembles a non-fruitbearing tree, that is not so. From this statement, we learn that the Radbaz maintains that there is no prohibition against grafting a vegetable onto a non-fruitbearing tree. This point is a matter of discussion among the commentaries.

[The following laws apply when a person] buries a bundle24If, however, they are not tied as a bundle, more stringent laws apply as indicated in the conclusion of the halachah. The rationale is that the fact that the vegetables are tied in a bundle indicates that they were placed in the earth for storage - in that era, there was no refrigeration - and not so that they would grow. of turnips, radishes, or the like under a tree, or even under a vine.25The Rambam mentions a vine, because that is the wording used in his source (ibid.), but it applies to other trees as well.
From the connection to the initial clause of the halachah and from the fact that other trees aside from a vine are mentioned, we can conclude that this clause also focuses on grafting. For there is no prohibition against planting vegetables in an orchard of trees other than a vineyard. What grafting is involved? It is possible to explain that the intermingling of the roots of the vegetable and the roots of the tree or vine could be considered as grafting (Rambam LeAm).
If some of the leaves were revealed, he need not be concerned [about the prohibition against kilayim],26Nor those involving the Sabbatical year, the tithes, or the Sabbath labors (ibid.). since he does not desire that [the buried vegetables] take root. If they were not [tied in] a bundle or their leaves were not revealed,27For this is not the ordinary way to plant these vegetable. The Ra'avad rules that the prohibition against kilayim does not apply even when the leaves are not revealed. The Radbaz and the Kessef Mishneh, however, justify the Rambam's view. The Shulchan Aruch (Yoreh De'ah 297:11) quotes the Rambam's ruling. he must show concern for that prohibition.

הלכה יב
שָׂדֶה שֶׁהָיְתָה זְרוּעָה וְקָצַר הַזֶּרַע וְנִשְׁאֲרוּ הָעִקָּרִין בָּאָרֶץ אַף עַל פִּי שֶׁאֵין מוֹצִיאִין צֶמַח אֶלָּא אַחַר כַּמָּה שָׁנִים לֹא יִהְיֶה זוֹרֵעַ בְּאוֹתָהּ שָׂדֶה מִין אַחֵר עַד שֶׁיַּעֲקֹר הָעִקָּרִין:
כסף משנה
12.
When a field had been sown and the produce [that grew] was harvested, but the roots were left in the earth, one should not sow another type of produce in that field until the roots are removed. [This applies] even if [these roots] will not produce a plant for several years.28The Rambam's ruling is based on his interpretation of Kilayim 2:5. The Ra'avad objects, offering a different understanding of that mishnah. The Shulchan Aruch (Yoreh De'ah 297:12) follows the Rambam's understanding.

הלכה יג
הָיְתָה שָׂדֵהוּ זְרוּעָה חִטִּים וְנִמְלַךְ לְזָרְעָהּ שְׂעוֹרִים קֹדֶם שֶׁיִּצְמְחוּ הַחִטִּים. יַמְתִּין לָהּ עַד שֶׁיִּפָּסְדוּ הַחִטִּים וְיַתְלִיעוּ בָּאָרֶץ כְּמוֹ שְׁלֹשָׁה יָמִים אִם הָיְתָה שָׂדֵהוּ רָוָה וְאַחַר כָּךְ יְהַפְּכֶהָ בְּמַחְרֵשָׁה וְיִזְרַע הַמִּין הָאַחֵר. וְאֵינוֹ צָרִיךְ לְהַפֵּךְ אֶת כֻּלָּהּ עַד שֶׁלֹּא תִּשָּׁאֵר חִטָּה שֶׁלֹּא נֶעֶקְרָה אֶלָּא חוֹרֵשׁ אֶת הַשָּׂדֶה כְּדֶרֶךְ שֶׁחוֹרְשִׁין אוֹתָהּ קֹדֶם הַמָּטָר כְּדֵי שֶׁתִּרְוֶה:
כסף משנה
13.
When a person had sown wheat in his field and then changed his mind and decided to sow barley before the wheat grew, he must wait until the wheat seeds rot and decompose in the earth - i.e., three days if the field is well irrigated. Afterwards, he should turn the land upside down with a plow29For after these steps, the seeds that were planted initially will no longer grow [the Rambam's Commentary to the Mishnah (Kilayim 2:3)]. The Ra'avad differs and maintains that even one of these steps is sufficient. There is no need to both wait and plow. The Radbaz and the Kessef Mishneh justify the Rambam's view. The Shulchan Aruch (Yoreh De'ah 297:13) follows the Rambam's understanding. and sow the other species. He does not have to turn the entire field upside down until there is not one kernel of wheat that has not been uprooted. Instead, he should plow the field like he would plow it before rainfall so that it would be watered thoroughly.

הלכה יד
צָמְחוּ הַחִטִּים וְאַחַר כָּךְ נִמְלַךְ לְזָרְעָהּ שְׂעוֹרִים יַהֲפֹךְ וְאַחַר כָּךְ יִזְרַע. וְאִם הוֹרִיד בְּהֶמְתּוֹ לְתוֹכָהּ וְקִרְסְמָה אֶת הַצֶּמַח הֲרֵי זֶה מֻתָּר לִזְרֹעַ שָׁם מִין אַחֵר:
כסף משנה
14.
If the wheat grew and then he changed his mind and decided to sow barley, he should turn over the field30For the plowing will destroy the plants that have grown. In contrast to the previous halachah, in this instance, he does not have to wait three days, because we do not think that the seeds will produce another plant. and then sow it. If he let his animal into the field and it ate the growths, it is permitted to sow the other species.

הלכה טו
בְּאֶחָד בַּאֲדָר מַשְׁמִיעִין עַל הַכִּלְאַיִם. וְכָל אָדָם יוֹצֵא לְגִנָּתוֹ וּלְשָׂדֵהוּ וּמְנַקִּין אוֹתוֹ מִן הַכִּלְאַיִם. וּבַחֲמִשָּׁה עָשָׂר בּוֹ יוֹצְאִים שְׁלוּחֵי בֵּית דִּין וּמְסַבְּבִים לִבְדֹּק:
כסף משנה
15.
On the first of Adar, a pronouncement is made regarding [the need for concern for] kilayim.31This is the time when plants first begin to grow and it is able to see whether one's fields and orchards have mixed species growing in them or not. Every person should go out to his garden and his field and clean it from mixed species. On the fifteenth of [Adar], the agents of the courts go out and spread out [throughout the land] to check.

הלכה טז
בָּרִאשׁוֹנָה הָיוּ עוֹקְרִין וּמַשְׁלִיכִין וְהָיוּ בַּעֲלֵי בָּתִּים שְׂמֵחִים שֶׁמְּנַקִּין לָהֶן שְׂדוֹתֵיהֶן. הִתְקִינוּ שֶׁיִּהְיוּ מַפְקִירִין אֶת כָּל הַשָּׂדֶה שֶׁיִּמְצְאוּ בּוֹ כִּלְאַיִם. וְהוּא שֶׁיִּמְצְאוּ בָּהּ מִין אַחֵר אֶחָד מֵאַרְבָּעָה וְעֶשְׂרִים אֲבָל פָּחוֹת מִיכַּן לֹא יִגְּעוּ בָּהּ:
כסף משנה
16.
Originally, [the agents of the court] would uproot [the mixed species] and cast them out and the owners of the fields would be happy that [the court's agents] would be cleaning their fields.32And hence, they would be lax in doing so themselves. [As a safeguard against indolence, the court ordained] that they would declare ownerless33See the Sefer Meirat Einayim 273:27 which states that according to the Shulchan Aruch (and the Rambam) the court's agents must declare the field ownerless. According to the Tur, by contrast, if a person sees mixed species are growing in a field, he may take possession of it, for it is considered ownerless even though the court has not made a declaration to that effect as of yet. any field where mixed species were found, provided the [additional] species was one twenty-fourth [of the entire crop]. If it is less than that, they should not touch it.

הלכה יז
וְחוֹזְרִין שְׁלוּחֵי בֵּית דִּין בְּחֻלּוֹ שֶׁל מוֹעֵד הַפֶּסַח לִרְאוֹת הָאֲפִיל שֶׁיָּצָא. וְכִלְאַיִם שֶׁהֵנֵצּוּ אֵין מַמְתִּינִים לָהֶן אֶלָּא יוֹצְאִין עֲלֵיהֶן מִיָּד וּמַפְקִירִין אֶת כָּל הַשָּׂדֶה אִם יֵשׁ בָּהּ אֶחָד מֵעֶשְׂרִים וְאַרְבָּעָה:
כסף משנה
17.
The agents of the court return during the intermediate days of Pesach to look at the crop that were late in ripening. If mixed species have budded, we do not wait. Instead, [the agents] go out immediately and declare the entire field ownerless if one twenty-fourth of it is from a second species.

זרעים הלכות כלאים פרק ב
Zeraim Kilayim Chapter 2